Silica-coated alumina activator-supports for metallocene catalyst compositions

ABSTRACT

Silica-coated alumina activator-supports, and catalyst compositions containing these activator-supports, are disclosed. Methods also are provided for preparing silica-coated alumina activator-supports, for preparing catalyst compositions, and for using the catalyst compositions to polymerize olefins.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/494,674, filed on Apr. 24, 2017, now U.S. Pat. No.10,239,975, which is a continuation application of U.S. patentapplication Ser. No. 15/097,355, filed on Apr. 13, 2016, now U.S. Pat.No. 9,670,296, which is a continuation application of U.S. patentapplication Ser. No. 12/980,415, filed on Dec. 29, 2010, now U.S. Pat.No. 9,346,896, which is a divisional application of U.S. patentapplication Ser. No. 12/565,257, filed on Sep. 23, 2009, now U.S. Pat.No. 7,884,163, which is a continuation-in-part of U.S. patentapplication Ser. No. 12/052,620, filed on Mar. 20, 2008, the disclosuresof which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of olefinpolymerization catalysis, catalyst compositions, methods for thepolymerization and copolymerization of olefins, and polyolefins. Morespecifically, this invention relates to chemically-treated silica-coatedalumina activator-supports and to catalyst compositions employing theseactivator-supports.

SUMMARY OF THE INVENTION

The present invention is directed generally to chemically-treatedsilica-coated alumina activator-supports, catalyst compositionsemploying these supports, methods for preparing activator-supports andcatalyst compositions, methods for using the catalyst compositions topolymerize olefins, the polymer resins produced using such catalystcompositions, and articles produced using these polymer resins. Inparticular, the present invention relates to chemically-treatedsilica-coated alumina activator-supports and to catalyst compositionsemploying such activator-supports. Catalyst compositions containingsilica-coated alumina activator-supports of the present invention can beused to produce, for example, ethylene-based homopolymers, copolymers,terpolymers, and the like.

In aspects of the present invention, activator-supports are disclosedwhich comprise at least one silica-coated alumina treated with at leastone electron-withdrawing anion. Generally, these silica-coated aluminashave a weight ratio of alumina to silica in a range from about 1:1 toabout 100:1, for example, from about 2:1 to about 20:1. The at least oneelectron-withdrawing anion can comprise fluoride, chloride, bromide,phosphate, triflate, bisulfate, sulfate, and the like, or anycombination thereof. Further, two or more electron-withdrawing anionscan be employed, examples of which can include, but are not limited to,fluoride and phosphate, fluoride and sulfate, chloride and phosphate,chloride and sulfate, triflate and sulfate, or triflate and phosphate,and the like.

Catalyst compositions containing these silica-coated activator-supportsare also disclosed in the present invention. In one aspect, the catalystcomposition can comprise at least one transition metal compound ormetallocene compound and at least one activator-support. The at leastone activator-support can comprise at least one silica-coated aluminahaving a weight ratio of alumina to silica in a range from about 1:1 toabout 100:1, and is treated with at least one electron-withdrawing anionsuch as, for example, fluoride, chloride, bromide, phosphate, triflate,bisulfate, sulfate, and the like, or combinations thereof. This catalystcomposition can further comprise at least one organoaluminum compound.In other aspects, the catalyst composition—comprising at least onetransition metal or metallocene compound and at least oneactivator-support—can further comprise at least one optionalco-catalyst. Suitable optional co-catalysts in this aspect can include,but are not limited to, aluminoxane compounds, organoboron ororganoborate compounds, ionizing ionic compounds, and the like, orcombinations thereof.

Another catalyst composition contemplated herein comprises at least onetransition metal or metallocene compound, at least one organoaluminumcompound, and at least one activator-support. The at least oneorganoaluminum compound can comprise, for instance, trimethylaluminum,triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum,diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminumchloride, or combinations thereof. The at least one activator-supportcomprises at least one silica-coated alumina treated with at least oneelectron-withdrawing anion, such as those electron-withdrawing anionsdescribed herein. The silica-coated alumina has a weight ratio ofalumina to silica in a range from about 1:1 to about 100:1, or fromabout 2:1 to about 20:1, in aspects of the invention.

Catalyst compositions disclosed herein can be used to polymerize olefinsto form homopolymers, copolymers, and the like. One such olefinpolymerization process can comprise contacting a catalyst composition ofthe present invention with at least one olefin monomer and optionally atleast one olefin comonomer under polymerization conditions to produce anolefin polymer, wherein the catalyst composition comprises at least onetransition metal or metallocene compound and at least oneactivator-support. As disclosed, the at least one activator-supportcomprises at least silica-coated alumina treated with at least oneelectron-withdrawing anion, and the silica-coated alumina generally hasa weight ratio of alumina to silica in a range from about 1:1 to about100:1. Other co-catalysts, including organoaluminum compounds, can beemployed in the olefin polymerization process.

Polymers produced from the polymerization of olefins, resulting inhomopolymers, copolymers, and the like, can be used to produce variousarticles of manufacture.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 presents a plot of catalyst activity, in units of grams ofpolyethylene per gram of activator-support (A-S) per hour, versus theconcentration of MET 1, in units of micromoles of MET 1 per gram of theA-S, for the activator-supports of Examples 1-3.

FIG. 2 presents a plot of catalyst activity, in units of grams ofpolyethylene per gram of MET 1 per hour, versus the concentration of MET1, in units of micromoles of MET 1 per gram of the activator-support(A-S), for the activator-supports of Examples 1-3.

FIG. 3 presents a plot of catalyst activity, in units of grams ofpolyethylene per gram of A-S per hour, versus the concentration of MET2, in units of micromoles of MET 2 per gram of the A-S, for theactivator-supports of Examples 1-3.

FIG. 4 presents a plot of catalyst activity, in units of grams ofpolyethylene per gram of MET 2 per hour, versus the concentration of MET2, in units of micromoles of MET 2 per gram of the A-S, for theactivator-supports of Examples 1-3.

FIG. 5 presents a plot of catalyst activity, in units of grams ofpolyethylene per hour, for the precontacted catalyst system and thecatalyst system which was not precontacted of Example 6.

FIG. 6 presents a plot of catalyst activity, in units of grams ofpolyethylene per gram of A-S per hour, versus the concentration of MET3, in units of micromoles of MET 3 per gram of the A-S, for theactivator-supports of Examples 2-3.

FIG. 7 presents a plot of catalyst activity, in units of grams ofpolyethylene per gram of MET 3 per hour, versus the concentration of MET3, in units of micromoles of MET 3 per gram of the A-S, for theactivator-supports of Examples 2-3.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. To the extent that any definition or usage provided by anydocument incorporated herein by reference conflicts with the definitionor usage provided herein, the definition or usage provided hereincontrols.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and so forth. A copolymer isderived from an olefin monomer and one olefin comonomer, while aterpolymer is derived from an olefin monomer and two olefin comonomers.Accordingly, “polymer” encompasses copolymers, terpolymers, etc.,derived from any olefin monomer and comonomer(s) disclosed herein.Similarly, an ethylene polymer would include ethylene homopolymers,ethylene copolymers, ethylene terpolymers, and the like. As an example,an olefin copolymer, such as an ethylene copolymer, can be derived fromethylene and a comonomer, such as 1-butene, 1-hexene, or 1-octene. Ifthe monomer and comonomer were ethylene and 1-hexene, respectively, theresulting polymer would be categorized an as ethylene/1-hexenecopolymer.

In like manner, the scope of the term “polymerization” includeshomopolymerization, copolymerization, terpolymerization, etc. Therefore,a copolymerization process would involve contacting one olefin monomer(e.g., ethylene) and one olefin comonomer (e.g., 1-hexene) to produce acopolymer.

The term “co-catalyst” is used generally herein to refer toorganoaluminum compounds that can constitute one component of a catalystcomposition. Additionally, “co-catalyst” also refers to other optionalcomponents of a catalyst composition including, but not limited to,aluminoxanes, organoboron or organoborate compounds, ionizing ioniccompounds, as disclosed herein. The term “co-catalyst” is usedregardless of the actual function of the compound or any chemicalmechanism by which the compound may operate. In one aspect of thisinvention, the term “co-catalyst” is used to distinguish that componentof the catalyst composition from the transition metal or metallocenecompound.

The term “fluoroorgano boron compound” is used herein with its ordinarymeaning to refer to neutral compounds of the form BY₃. The term“fluoroorgano borate compound” also has its usual meaning to refer tothe monoanionic salts of a fluoroorgano boron compound of the form[cation]⁺[BY₄]⁻, where Y represents a fluorinated organic group.Materials of these types are generally and collectively referred to as“organoboron or organoborate compounds.”

The term “contact product” is used herein to describe compositionswherein the components are contacted together in any order, in anymanner, and for any length of time. For example, the components can becontacted by blending or mixing. Further, contacting of any componentcan occur in the presence or absence of any other component of thecompositions described herein. Combining additional materials orcomponents can be done by any suitable method. Further, the term“contact product” includes mixtures, blends, solutions, slurries,reaction products, and the like, or combinations thereof. Although“contact product” can include reaction products, it is not required forthe respective components to react with one another. Similarly, the term“contacting” is used herein to the refer to materials which may beblended, mixed, slurried, dissolved, reacted, treated, or otherwisecontacted in some other manner.

The term “precontacted” mixture is used herein to describe a firstmixture of catalyst components that are contacted for a first period oftime prior to the first mixture being used to form a “postcontacted” orsecond mixture of catalyst components that are contacted for a secondperiod of time. Often, the precontacted mixture describes a mixture ofmetallocene or transition metal compound (or compounds), olefin monomer(or monomers), and organoaluminum compound (or compounds), before thismixture is contacted with a calcined chemically-treated solid oxide (oroxides) and optional additional organoaluminum compound(s). Theprecontacted mixture also can describe a mixture of metallocene compoundor transition metal compound (or compounds), organoaluminum compound (orcompounds), and activator-support compound (or compounds) which iscontacted for a period of time prior to being fed to a polymerizationreactor. Thus, precontacted describes components that are used tocontact each other, but prior to contacting the components in thesecond, postcontacted mixture. Accordingly, this invention mayoccasionally distinguish between a component used to prepare theprecontacted mixture and that component after the mixture has beenprepared. For example, in one aspect of this invention, it is possiblefor a precontacted organoaluminum compound, once it is contacted with ametallocene and an olefin monomer, to have reacted to form at least onedifferent chemical compound, formulation, or structure from the distinctorganoaluminum compound used to prepare the precontacted mixture. Inthis case, the precontacted organoaluminum compound or component isdescribed as comprising an organoaluminum compound that was used toprepare the precontacted mixture.

Additionally, the precontacted mixture can describe a mixture ofmetallocene or transition metal compound(s) and organoaluminumcompound(s), prior to contacting this mixture with the calcinedchemically-treated solid oxide(s). This precontacted mixture also candescribe a mixture of metallocene compound(s), olefin monomer(s), andcalcined chemically-treated solid oxide(s), before this mixture iscontacted with an organoaluminum co-catalyst compound or compounds.

Similarly, the term “postcontacted” mixture is used herein to describe asecond mixture of catalyst components that are contacted for a secondperiod of time, and one constituent of which is the “precontacted” orfirst mixture of catalyst components that were contacted for a firstperiod of time. For example, the term “postcontacted” mixture is usedherein to describe the mixture of metallocene or transition metalcompound(s), olefin monomer(s), organoaluminum compound(s), and calcinedchemically-treated solid oxide(s) formed from contacting theprecontacted mixture of a portion of these components with anyadditional components added to make up the postcontacted mixture. Forinstance, the additional component added to make up the postcontactedmixture can be a chemically-treated solid oxide, and optionally, caninclude an organoaluminum compound which is the same as or differentfrom the organoaluminum compound used to prepare the precontactedmixture, as described herein. Accordingly, this invention may alsooccasionally distinguish between a component used to prepare thepostcontacted mixture and that component after the mixture has beenprepared.

The term “metallocene,” as used herein, describes a compound comprisingat least one η³ to η⁵-cycloalkadienyl-type moiety, wherein η³ toη⁵-cycloalkadienyl moieties include cyclopentadienyl ligands, indenylligands, fluorenyl ligands, and the like, including partially saturatedor substituted derivatives or analogs of any of these. Possiblesubstituents on these ligands may include hydrogen, therefore thedescription “substituted derivatives thereof” in this inventioncomprises partially saturated ligands such as tetrahydroindenyl,tetrahydrofluorenyl, octahydrofluorenyl, partially saturated indenyl,partially saturated fluorenyl, substituted partially saturated indenyl,substituted partially saturated fluorenyl, and the like. In somecontexts, the metallocene is referred to simply as the “catalyst,” inmuch the same way the term “co-catalyst” is used herein to refer to, forexample, an organoaluminum compound. Metallocene also is used herein toencompass mono-cyclopentadienyl or half-sandwich compounds, as well ascompounds containing at least one cyclodienyl ring and compoundscontaining boratabenzene ligands. Further, metallocene also is usedherein to encompass dinuclear metallocene compounds, i.e., compoundscomprising two metallocene moieties linked by a connecting group, suchas an alkenyl group resulting from an olefin metathesis reaction or asaturated version resulting from hydrogenation or derivatization. Unlessotherwise specified, the following abbreviations are used: Cp forcyclopentadienyl; Ind for indenyl; and Flu for fluorenyl.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the components of thecomposition/mixture, the nature of the active catalytic site, or thefate of the co-catalyst, the metallocene or transition metal compound,any olefin monomer used to prepare a precontacted mixture, or thechemically-treated solid oxide, after combining these components.Therefore, the terms “catalyst composition,” “catalyst mixture,”“catalyst system,” and the like, can include both heterogeneouscompositions and homogenous compositions.

The terms “chemically-treated solid oxide,” “activator-support,”“treated solid oxide,” and the like, are used herein to describe asolid, inorganic oxide of relatively high porosity, which exhibits Lewisacidic or Brønsted acidic behavior, and which has been treated with anelectron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the chemically-treatedsolid oxide comprises a calcined contact product of at least one solidoxide with at least one electron-withdrawing anion source compound.Typically, the chemically-treated solid oxide comprises at least oneionizing, acidic solid oxide. The terms “support” and“activator-support” are not used to imply these components are inert,and such components should not be construed as an inert component of thecatalyst composition.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices, and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention. The publications discussed throughout the text are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that theinventors are not entitled to antedate such disclosure by virtue ofprior invention.

For any particular compound disclosed herein, any general or specificstructure presented also encompasses all conformational isomers,regioisomers, and stereoisomers that may arise from a particular set ofsubstituents. The general or specific structure also encompasses allenantiomers, diastereomers, and other optical isomers whether inenantiomeric or racemic forms, as well as mixtures of stereoisomers, aswould be recognized by a skilled artisan.

Applicants disclose several types of ranges in the present invention.These include, but are not limited to, a range of a number of carbonatoms, a range of weight ratios, a range or molar ratios, a range ofsurface areas, a range of pore volumes, a range of particle sizes, arange of catalyst activities, and so forth. When Applicants disclose orclaim a range of any type, Applicants' intent is to disclose or claimindividually each possible number that such a range could reasonablyencompass, including end points of the range as well as any sub-rangesand combinations of sub-ranges encompassed therein. For example, whenthe Applicants disclose or claim a weight ratio of alumina to silica ina silica-coated alumina, Applicants' intent is to disclose or claimindividually every possible number that such a range could encompass,consistent with the disclosure herein. By a disclosure that the weightratio of alumina to silica in a silica-coated alumina is in a range fromabout 1:1 to about 100:1, Applicants intend to recite that the weightratio can be selected from about 1:1, about 1.1:1, about 1.2:1, about1.3:1, about 1.4:1, about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1,about 1.9:1, about 2:1, about 2.1:1, about 2.2:1, about 2.3:1, about2.4:1, about 2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1,about 3:1, about 3.1:1, about 3.2:1, about 3.3:1, about 3.4:1, about3.5:1, about 3.6:1, about 3.7:1, about 3.8:1, about 3.9:1, about 4:1,about 4.1:1, about 4.2:1, about 4.3:1, about 4.4:1, about 4.5:1, about4.6:1, about 4.7:1, about 4.8:1, about 4.9:1, about 5:1, about 5.1:1,about 5.2:1, about 5.3:1, about 5.4:1, about 5.5:1, about 5.6:1, about5.7:1, about 5.8:1, about 5.9:1, about 6:1, about 6.5:1, about 7:1,about 7.5:1, about 8:1, about 8.5:1, about 9:1, about 9.5:1, about 10:1,about 11:1, about 12:1, about 13:1, about 14:1, about 15:1, about 16:1,about 17:1, about 18:1, about 19:1, about 20:1, about 30:1, about 40:1,about 50:1, about 60:1, about 70:1, about 80:1, about 90:1, about 95:1,about 96:1, about 97:1, about 98:1, about 99:1, or about 100:1.Additionally, the weight ratio can be within any range from about 1:1 toabout 100:1 (for example, the weight ratio is in a range from about 2:1to about 20:1), and this also includes any combination of ranges betweenabout 1:1 to about 100:1 (for example, the weight ratio is in a rangefrom about 1.8:1 to about 12:1 or from about 20:1 to about 40:1).Likewise, all other ranges disclosed herein should be interpreted in amanner similar to this example.

Applicants reserve the right to proviso out or exclude any individualmembers of any such group, including any sub-ranges or combinations ofsub-ranges within the group, that can be claimed according to a range orin any similar manner, if for any reason Applicants choose to claim lessthan the full measure of the disclosure, for example, to account for areference that Applicants may be unaware of at the time of the filing ofthe application. Further, Applicants reserve the right to proviso out orexclude any individual substituents, analogs, compounds, ligands,structures, or groups thereof, or any members of a claimed group, if forany reason Applicants choose to claim less than the full measure of thedisclosure, for example, to account for a reference that Applicants maybe unaware of at the time of the filing of the application.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one, unless otherwise specified. Forinstance, the disclosure of “an activator-support” or “a metallocenecompound” is meant to encompass one, or mixtures or combinations of morethan one, activator-support or metallocene compound, respectively.

While compositions and methods are described in terms of “comprising”various components or steps, the compositions and methods can also“consist essentially of” or “consist of” the various components orsteps. For example, a catalyst composition in an aspect of the presentinvention can comprise; alternatively, can consist essentially of; oralternatively, can consist of; (i) at least one transition metal ormetallocene compound, (ii) at least one activator-support, and (iii) atleast one organoaluminum compound.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to chemically-treatedsilica-coated alumina activator-supports, catalyst compositionsemploying these supports, methods for preparing activator-supports andcatalyst compositions, methods for using the catalyst compositions topolymerize olefins, the polymer resins produced using such catalystcompositions, and articles produced using these polymer resins.

In particular, the present invention is directed to chemically-treatedsilica-coated alumina activator-supports and to catalyst compositionsemploying such activator-supports. Catalyst compositions containing thesilica-coated alumina supports of the present invention can be used toproduce, for example, ethylene-based homopolymers and copolymers.

Catalyst Compositions

Catalyst compositions disclosed herein employ at least one silica-coatedalumina activator-support. According to one aspect of the presentinvention, a catalyst composition is provided which comprises:

(a) at least one transition metal compound or metallocene compound; and

(b) at least one activator-support.

The at least one activator-support comprises at least one silica-coatedalumina, having a weight ratio of alumina to silica ranging from about1:1 to about 100:1, which is treated with at least oneelectron-withdrawing anion. The at least one electron-withdrawing anioncan comprise, for example, fluoride, chloride, bromide, phosphate,triflate, bisulfate, sulfate, and the like, or combinations thereof.This catalyst composition can further comprise at least oneorganoaluminum compound. These catalyst compositions can be utilized toproduce polyolefins—homopolymers, copolymers, and the like—for a varietyof end-use applications.

In accordance with this and other aspects of the present invention, itis contemplated that the catalyst compositions disclosed herein cancontain more than one transition metal compound and/or more than onemetallocene compound and/or more than one activator-support.Additionally, more than one organoaluminum compound also iscontemplated.

In another aspect of the present invention, a catalyst composition isprovided which comprises at least one transition metal or metallocenecompound, at least one activator-support, and, optionally, at least oneorganoaluminum compound, wherein this catalyst composition issubstantially free of aluminoxanes, organoboron or organoboratecompounds, and ionizing ionic compounds. In this aspect, the catalystcomposition has catalyst activity, to be discussed below, in the absenceof these additional or optional co-catalysts.

However, in other aspects of this invention, optional co-catalysts canbe employed. For example, a catalyst composition comprising at least onemetallocene or transition metal compound and at least oneactivator-support can further comprise at least one optionalco-catalyst. Suitable co-catalysts in this aspect can include, but arenot limited to, aluminoxane compounds, organoboron or organoboratecompounds, ionizing ionic compounds, and the like, or combinationsthereof. More than one co-catalyst can be present in the catalystcomposition.

Another catalyst composition contemplated herein comprises:

(a) at least one transition metal compound or metallocene compound;

(b) at least one activator-support; and

(c) at least one organoaluminum compound.

The at least one activator-support comprises at least one silica-coatedalumina treated with at least one electron-withdrawing anion. The atleast one silica-coated alumina has a weight ratio of alumina to silicain a range from about 1:1 to about 100:1, or from about 2:1 to about20:1, in this aspect of the invention. The at least oneelectron-withdrawing anion can comprise fluoride, chloride, bromide,phosphate, triflate, bisulfate, sulfate, and the like, or combinationsthereof. Often, the at least one organoaluminum compound can comprisetrimethylaluminum, triethylaluminum, tri-n-propylaluminum,tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminumethoxide, diethylaluminum chloride, or any combination thereof.

Catalyst compositions of the present invention comprising at least onetransition metal or metallocene compound and at least onechemically-treated silica-coated alumina activator-support can furthercomprise at least one additional or optional activator-support. Forinstance, optional activator-supports such as fluorided alumina,chlorided alumina, bromided alumina, sulfated alumina, fluoridedsilica-alumina, chlorided silica-alumina, bromided silica-alumina,sulfated silica-alumina, fluorided silica-zirconia, chloridedsilica-zirconia, bromided silica-zirconia, sulfated silica-zirconia,fluorided silica-titania, and the like, or combinations thereof, can beemployed in catalyst compositions disclosed herein. If the additional oroptional activator-support is a chemically-treated silica-alumina, thismaterial is different from the silica-coated aluminas of the presentinvention, to be discussed further below. One or more organoaluminumcompounds also can be present in the catalyst composition.

In another aspect, a catalyst composition comprising at least onetransition metal or metallocene compound and at least one silica-coatedalumina activator-support—and optionally, at least one organoaluminumcompound—can further comprise at least one additional or optionalactivator-support, wherein the at least one optional activator-supportcomprises at least one solid oxide treated with at least oneelectron-withdrawing anion. The at least one solid oxide can comprisesilica, alumina, silica-alumina, aluminum phosphate,heteropolytungstate, titania, zirconia, magnesia, boria, zinc oxide, anymixed oxide thereof, or any mixture thereof; and the at least oneelectron-withdrawing anion can comprise sulfate, bisulfate, fluoride,chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, or any combination thereof.

Further, activator-supports of this invention can comprise a metal ormetal ion such as, for example, zinc, titanium, nickel, vanadium,silver, copper, gallium, tin, tungsten, molybdenum, and the like, or anycombination thereof.

In yet another aspect, catalyst compositions of the present inventioncan further comprise one or more optional activator-supports selectedfrom a clay mineral, a pillared clay, an exfoliated clay, an exfoliatedclay gelled into another oxide matrix, a layered silicate mineral, anon-layered silicate mineral, a layered aluminosilicate mineral, anon-layered aluminosilicate mineral, and the like, or combinations ofthese materials. Additional, or optional, activator-support materialswill be discussed in more detail below.

In one aspect, the present invention encompasses a catalyst compositioncomprising at least one transition metal or metallocene compound and atleast one activator-support. The at least one activator-support cancomprise at least one silica-coated alumina treated with at least oneelectron-withdrawing anion. The weight ratio of alumina to silica in theat least one silica-coated alumina can range from about 1:1 to about100:1, for example, from about 1.5:1 to about 100:1, from about 2:1 toabout 20:1, or from about 2:1 to about 12:1. This catalyst compositioncan further comprise at least one organoaluminum compound. Additionally,this catalyst composition can further comprise at least one optionalco-catalyst, wherein the at least one optional co-catalyst is at leastone aluminoxane compound, at least one organoboron or organoboratecompound, at least one ionizing ionic compound, or any combinationthereof.

This invention further encompasses methods of making these catalystcompositions, such as, for example, contacting the respective catalystcomponents in any order or sequence.

The at least one transition metal and/or metallocene compound can beprecontacted with an olefinic monomer if desired, not necessarily theolefin monomer to be polymerized, and an organoaluminum compound for afirst period of time prior to contacting this precontacted mixture withan activator-support. The first period of time for contact, theprecontact time, between the transition metal and/or metallocenecompound (or compounds), the olefinic monomer, and the organoaluminumcompound typically ranges from a time period of about 1 minute to about24 hours, for example, from about 3 minutes to about 1 hour. Precontacttimes from about 10 minutes to about 30 minutes are also employed.

Alternatively, the precontacting process is carried out in multiplesteps, rather than a single step, in which multiple mixtures areprepared, each comprising a different set of catalyst components. Forexample, at least two catalyst components are contacted forming a firstmixture, followed by contacting the first mixture with at least oneother catalyst component forming a second mixture, and so forth.

Multiple precontacting steps can be carried out in a single vessel or inmultiple vessels. Further, multiple precontacting steps can be carriedout in series (sequentially), in parallel, or a combination thereof. Forexample, a first mixture of two catalyst components can be formed in afirst vessel, a second mixture comprising the first mixture plus oneadditional catalyst component can be formed in the first vessel or in asecond vessel, which is typically placed downstream of the first vessel.

In another aspect, one or more of the catalyst components can be splitand used in different precontacting treatments. As an example, part of acatalyst component is fed into a first precontacting vessel forprecontacting with at least one other catalyst component, while theremainder of that same catalyst component is fed into a secondprecontacting vessel for precontacting with at least one other catalystcomponent, or is fed directly into the reactor, or a combinationthereof. The precontacting can be carried out in any suitable equipment,such as tanks, stirred mix tanks, various static mixing devices, aflask, a vessel of any type, or combinations of these apparatus.

In another aspect of this invention, the various catalyst components(for example, transition metal or metallocene compound,activator-support, organoaluminum co-catalyst, and optionally anunsaturated hydrocarbon) are contacted in the polymerization reactorsimultaneously while the polymerization reaction is proceeding.Alternatively, any two or more of these catalyst components can beprecontacted in a vessel prior to entering the reaction zone. Thisprecontacting step can be continuous, in which the precontacted productis fed continuously to the reactor, or it can be a stepwise or batchwiseprocess in which a batch of precontacted product is added to make acatalyst composition. This precontacting step can be carried out over atime period that can range from a few seconds to as much as severaldays, or longer. In this aspect, the continuous precontacting stepgenerally lasts from about 1 second to about 1 hour. In another aspect,the continuous precontacting step lasts from about 10 seconds to about45 minutes, or from about 1 minute to about 30 minutes.

Once a precontacted mixture of the transition metal and/or metallocenecompound(s), olefin monomer(s), and organoaluminum co-catalyst(s) iscontacted with the activator-support(s), this composition (with theaddition of the activator-support) is termed the “postcontactedmixture.” The postcontacted mixture optionally remains in contact for asecond period of time, the postcontact time, prior to initiating thepolymerization process. Postcontact times between the precontactedmixture and the activator-support generally range from about 1 minute toabout 24 hours. In a further aspect, the postcontact time can be in arange from about 1 minute to about 1 hour. The precontacting step, thepostcontacting step, or both, can increase the productivity of thepolymer as compared to the same catalyst composition that is preparedwithout precontacting or postcontacting. However, neither aprecontacting step nor a postcontacting step is required.

The postcontacted mixture can be heated at a temperature and for a timeperiod sufficient to allow adsorption, impregnation, or interaction ofprecontacted mixture and the activator-support, such that a portion ofthe components of the precontacted mixture is immobilized, adsorbed, ordeposited thereon. Where heating is employed, the postcontacted mixturegenerally is heated to a temperature of from between about 0° F. toabout 150° F., or from about 40° F. to about 95° F.

In another aspect, a metallocene, an organoaluminum, and anactivator-support can be precontacted for a period of time prior tobeing contacted with the olefin to be polymerized in the reactor, asdemonstrated in Example 6 that follows.

According to one aspect of this invention, the molar ratio of the molesof transition metal or metallocene compound to the moles oforganoaluminum compound in a catalyst composition generally is in arange from about 1:1 to about 1:10,000. In another aspect, the molarratio is in a range from about 1:1 to about 1:1,000. Yet, in anotheraspect, the molar ratio of the moles of metallocene or transition metalcompound to the moles of organoaluminum compound is in a range fromabout 1:1 to about 1:100. These molar ratios reflect the ratio of totalmoles of transition metal and/or metallocene compound (or compounds) tothe total amount of organoaluminum compound (or compounds) in both theprecontacted mixture and the postcontacted mixture combined, ifprecontacting and/or postcontacting steps are employed.

When a precontacting step is used, the molar ratio of the total moles ofolefin monomer to total moles of transition metal and/or metallocenecompound(s) in the precontacted mixture is typically in a range fromabout 1:10 to about 100,000:1. Total moles of each component are used inthis ratio to account for aspects of this invention where more than oneolefin monomer and/or more than one transition metal and/or metallocenecompound is employed. Further, this molar ratio can be in a range fromabout 10:1 to about 1,000:1 in another aspect of the invention.

Generally, the weight ratio of organoaluminum compound toactivator-support is in a range from about 10:1 to about 1:1000. If morethan one organoaluminum compound and/or more than one activator-supportis employed, this ratio is based on the total weight of each respectivecomponent. In another aspect, the weight ratio of the organoaluminumcompound to the activator-support is in a range from about 3:1 to about1:100, or from about 1:1 to about 1:50.

In some aspects of this invention, the weight ratio of transition metalor metallocene to activator-support is in a range from about 1:1 toabout 1:1,000,000. If more than one transition metal and/or metallocenecompound and/or more than one activator-support is employed, this ratiois based on the total weight of each respective component. In anotheraspect, this weight ratio is in a range from about 1:5 to about1:100,000, or from about 1:10 to about 1:10,000. Yet, in another aspect,the weight ratio of the transition metal and/or metallocene compound(s)to the activator-support is in a range from about 1:20 to about 1:1000.

Yet, in another aspect of this invention, the concentration of thetransition metal or metallocene, in units of micromoles of thetransition metal or metallocene per gram of the activator-support, canbe in a range from about 0.5 to about 150. If more than one transitionmetal and/or metallocene and/or more than one activator-support isemployed, this ratio is based on the total weight of each respectivecomponent. In another aspect, the concentration of the transition metaland/or metallocene, in units of micromoles of the transition metaland/or metallocene per gram of the activator-support, can be in a rangefrom about 1 to about 120, for example, from about 5 to about 100, fromabout 5 to about 80, from about 5 to about 60, or from about 5 to about40. In still another aspect, the concentration of the transition metaland/or metallocene, in units of micromoles of the transition metaland/or metallocene per gram of the activator-support, is in a range fromabout 1 to about 30, from about 1 to about 20, from about 1 to about 15,or from about 1 to about 12.

According to some aspects of this invention, aluminoxane compounds arenot required to form the catalyst composition. Thus, the polymerizationproceeds in the absence of aluminoxanes. Accordingly, the presentinvention can use, for example, organoaluminum compounds and anactivator-support in the absence of aluminoxanes. While not intending tobe bound by theory, it is believed that the organoaluminum compoundlikely does not activate a transition metal or metallocene catalyst inthe same manner as an organoaluminoxane compound.

Additionally, in some aspects, organoboron and organoborate compoundsare not required to form a catalyst composition of this invention.Nonetheless, aluminoxanes, organoboron or organoborate compounds,ionizing ionic compounds, or combinations thereof can be used in othercatalyst compositions contemplated by and encompassed within the presentinvention. Hence, co-catalysts such as aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, or combinationsthereof, can be employed with the transition metal and/or metallocenecompound, and either in the presence or in the absence of anorganoaluminum compound.

In accordance with one aspect of this invention, a catalyst compositioncan comprise at least one transition metal or metallocene compound, andat least one activator-support. In accordance with another aspect ofthis invention, a catalyst composition can comprise at least onetransition metal or metallocene compound, at least oneactivator-support, and at least one organoaluminum compound. Catalystcompositions in these and other aspects of the present inventiongenerally have a catalyst activity greater than about 100 grams ofpolyethylene (homopolymer, copolymer, etc., as the context requires) pergram of activator-support per hour (abbreviated gPE/gA-S/hr). In anotheraspect, the catalyst activity can be greater than about 200, greaterthan about 300, greater than about 400, or greater than about 500gPE/gA-S/hr. In still another aspect, catalyst compositions of thisinvention can be characterized as having a catalyst activity greaterthan about 750, greater than about 1000, or greater than about 1500gPE/gA-S/hr. The catalyst activity can be greater than about 2000,greater than about 4000, or greater than about 5000 gPE/gA-S/hr, incertain aspects of this invention. The catalyst activity is measuredunder slurry polymerization conditions using isobutane as the diluent,at a polymerization temperature of 90° C. and a reactor pressure of 420psig. The reactor pressure is largely controlled by the pressure of themonomer, e.g., the ethylene pressure, but other contributors to thereactor pressure can include hydrogen gas (e.g., if hydrogen is used),isobutane vapor, and comonomer gas or vapor (e.g., if a comonomer isused).

Likewise, catalyst compositions of the present invention can have acatalyst activity greater than about 5000 grams of polyethylene(homopolymer, copolymer, etc., as the context requires) per gram oftransition metal compound or metallocene compound per hour (abbreviatedgPE/gMET/hr). For example, the catalyst activity can be greater thanabout 10,000, greater than about 25,000, or greater than about 50,000gPE/gMET/hr. In another aspect, catalyst compositions of this inventioncan be characterized as having a catalyst activity greater than about75,000, greater than about 100,000, or greater than about 150,000gPE/gMET/hr. Yet, in another aspect of this invention, the catalystactivity can be greater than about 200,000, greater than about 300,000,greater than about 400,000, or greater than about 500,000 gPE/gMET/hr.This catalyst activity is measured under slurry polymerizationconditions using isobutane as the diluent, at a polymerizationtemperature of about 90° C. and a reactor pressure of about 420 psig.

Catalyst compositions employing silica-coated alumina activatorsupports—for instance, fluorided silica-coated alumina—may result insignificant increases in catalyst activity, for instance, as compared toa conventional silica-alumina activator-support—for instance, fluoridedsilica-alumina—having an alumina to silica weight ratio of less than 1:1(e.g., from about 0.05:1 to about 0.25:1). These catalyst activities canbe compared on a “per gram of activator-support” basis or on a “per gramof transition metal or metallocene” basis. In one aspect, the catalystactivity of a catalyst composition of the present invention is at leasttwice that of a comparable catalyst composition containing aconventional silica-alumina activator-support (i.e., at the samereaction conditions, using the same other catalyst components, sameanion chemical treatment, etc.). In another aspect, the activity of acatalyst composition comprising a silica-coated aluminaactivator-support (with a weight ratio of alumina to silica in a rangeof, for example, from about 1.5:1 to about 100:1) can be at least about3 times, at least about 4 times, at least about 5 times, at least about6 times, or at least about 7 times the activity of a comparable catalystcomposition comprising a silica-alumina activator-support (having aweight ratio of alumina to silica in a range of, for example, from about0.05:1 to about 0.25:1). In still another aspect, the catalyst activityof a catalyst composition comprising a silica-coated aluminaactivator-support can be from about 2 times to about 100 times theactivity of a comparable catalyst composition comprising asilica-alumina activator-support. Yet, in another aspect, the catalystactivity of a catalyst composition comprising a silica-coated aluminaactivator-support can be from about 2 times to about 80 times;alternatively, from about 3 times to about 60 times; alternatively, fromabout 3 times to about 40 times; or alternatively, from about 4 times toabout 20 times; the activity of a comparable catalyst compositioncomprising a silica-alumina activator-support.

As discussed herein, any combination of the metallocene or transitionmetal compound, the activator-support, the organoaluminum compound, andthe olefin monomer, can be precontacted in some aspects of thisinvention. When any precontacting occurs with an olefinic monomer, it isnot necessary that the olefin monomer used in the precontacting step bethe same as the olefin to be polymerized. Further, when a precontactingstep among any combination of the catalyst components is employed for afirst period of time, this precontacted mixture can be used in asubsequent postcontacting step between any other combination of catalystcomponents for a second period of time. For example, a metallocenecompound, an organoaluminum compound, and 1-hexene can be used in aprecontacting step for a first period of time, and this precontactedmixture then can be contacted with a calcined chemically-treated solidoxide to form a postcontacted mixture that is contacted for a secondperiod of time prior to initiating the polymerization reaction. Forexample, the first period of time for contact, the precontact time,between any combination of the transition metal or metallocene compound,the olefinic monomer, the activator-support, and the organoaluminumcompound can be from about 1 minute to about 24 hours, from about 1minute to about 1 hour, or from about 10 minutes to about 30 minutes.The postcontacted mixture optionally is allowed to remain in contact fora second period of time, the postcontact time, prior to initiating thepolymerization process. According to one aspect of this invention,postcontact times between the precontacted mixture and any remainingcatalyst components is from about 1 minute to about 24 hours, or fromabout 0.1 hour to about 1 hour.

Silica-Coated Alumina Activator-Supports

Activator-supports of the present invention comprise silica-coatedaluminas, and these materials comprise an alumina matrix that is coated,or partially coated, with a layer of silica. These silica-coatedaluminas generally have a high alumina content, i.e., a weight ratio ofalumina to silica in the silica-coated alumina of greater than about1:1. Silica-coated alumina activator-supports provided in this inventioncan comprise at least one silica-coated alumina treated with at leastone electron-withdrawing anion, the at least one silica-coated aluminahaving a weight ratio of alumina to silica ranging, generally, fromabout 1:1 to about 100:1. The at least one electron-withdrawing aniontypically comprises fluoride, chloride, bromide, phosphate, triflate,bisulfate, sulfate, and the like, but combinations of two or more ofthese anions also can be employed.

In one aspect of this invention, the weight ratio of alumina to silicain the silica-coated alumina can be in a range from about 1:1 to about100:1, or from about 1.2:1 to about 25:1. In another aspect, the weightratio of alumina to silica in the silica-coated alumina is in a rangefrom about 1.1:1 to about 100:1; alternatively, from about 1.1:1 toabout 75:1; alternatively, from about 1.3:1 to about 50:1;alternatively, from about 1.5:1 to about 20:1; or alternatively, fromabout 1.5:1 to about 15:1. Yet, in another aspect, the weight ratio ofalumina to silica is in a range from about 2:1 to about 100:1, such as,for example, from about 2:1 to about 50:1, from about 2:1 to about 25:1,or from about 2:1 to about 20:1. For instance, the alumina to silicaweight ratio in a silica-coated alumina can be in a range from about 2:1to about 15:1, from about 2:1 to about 12:1, or from about 2:1 to about10:1. The alumina to silica weight ratio in the silica-coated aluminacan be from about 2.1:1 to about 9:1, from about 2.2:1 to about 8:1, orfrom about 2.3:1 to about 6:1, in other aspects disclosed herein.

High alumina content silica-coated aluminas of the present inventiongenerally have surface areas ranging from about 100 to about 1000 m²/g.In some aspects, the surface area falls within a range from about 150 toabout 750 m²/g, for example, from about 200 to about 600 m²/g. Thesurface area of the silica-coated alumina can range from about 250 toabout 500 m²/g in another aspect of this invention. High alumina contentsilica-coated aluminas having surface areas of about 300 m²/g, about 350m²/g, about 400 m²/g, or about 450 m²/g, can be employed in aspects ofthis invention.

The pore volume of the silica-coated aluminas is generally greater thanabout 0.5 mL/g. Often, the pore volume is greater than about 0.75 mL/g,or greater than about 1 mL/g. In another aspect, the pore volume isgreater than about 1.2 mL/g. In yet another aspect, the pore volumefalls within a range from about 0.5 mL/g to about 1.8 mL/g, such as, forexample, from about 0.8 mL/g to about 1.7 mL/g, or from about 1 mL/g toabout 1.6 mL/g.

The silica-coated aluminas disclosed herein generally have averageparticle sizes ranging from about 5 microns to about 150 microns. Insome aspects of this invention, the average particle size falls within arange from about 30 microns to about 100 microns. For example, theaverage particle size of silica-coated aluminas can be in a range fromabout 40 to about 80 microns.

Silica-coated aluminas of the present invention can be produced usingvarious methods, including those disclosed in U.S. Pat. No. 5,401,820,which is incorporated herein by reference in its entirety. In one aspectof this invention, a suitable method for producing a silica-coatedalumina can comprise the following steps:

(i) providing at least one alumina source, the at least one aluminasource comprising an alumina, a hydrated alumina, aluminum hydroxide,boehmite, or a combination thereof;

(ii) contacting the at least one alumina source with a solution orsuspension comprising at least one solvent and at least onesilicon-containing compound capable of producing silica uponcalcination;

(iii) depositing a coating of the at least one silicon-containingcompound on at least a portion of the at least one alumina source; and

(iv) removing the solvent.

Alumina sources for silica-coated aluminas can include, but are notlimited to, an alumina, a hydrated alumina, aluminum hydroxide,boehmite, or a combination thereof.

In one step of the process to produce a silica-coated alumina, thealumina source (or sources) is/are contacted with a solution orsuspension comprising at least one solvent and at least onesilicon-containing compound capable of producing silica uponcalcination. The alumina source may be wet or dry prior to thiscontacting step. Although not limited to any particular solvent(s),suitable solvents for the solution or suspension (e.g., dispersion,emulsion, and so forth) can include, for example, water, and organicsolvents such as hexane, heptane, benzene, toluene, xylene, and otherhydrocarbons, acetone, alcohols, and the like, or combinations thereof.

One or more silicon-containing compounds can be used to produce acoating of silica, for example, a partial coating on the alumina, a fullcoating on the alumina, etc. The silicon-containing compound generallyis a material that is capable of producing or liberating silica uponcalcination, and such materials can include, but are not limited to,silica, sodium silicate, potassium silicate, SiCl₄, Si(OMe)₄, Si(OEt)₄,siloxane polymers, silica colloids, silicic acid, and the like, orcombinations thereof.

In some aspects, a coating of the silicon-containing compound isdeposited on at least a portion of the alumina source, and the solventis removed. The solvent may be removed prior to, or during, a subsequentcalcination step. The coated alumina may be calcined before and/orduring and/or after the coated alumina is contacted with anelectron-withdrawing anion source. The result of this process is acoating of silica on the alumina, i.e., a partial coating, or a completecoating.

It should be noted that the silica-coated aluminas disclosed herein aredifferent from conventional silica-alumina solid oxides (e.g., mixedoxides), both in terms of morphology and the processes used to producethe respective materials. As noted above, silica-coated aluminas of thepresent invention have both a high alumina content (e.g., a weight ratioof alumina to silica in a range from about 1:1 to about 100:1) and acoating of silica (e.g., partial, complete) on an alumina matrix.Silica-aluminas are known materials typically having an alumina tosilica weight ratio of less than 1:1, and usually in a range from about0.05:1 to about 0.25:1, as illustrated in Example 1 that follows. Suchsilica-alumina materials are not the inventive silica-coated aluminas ofthis invention. It is believed that silica-alumina mixed oxides can beprepared by co-gelling or co-precipitating methods, which may result ina mixed matrix of silica and alumina (e.g., a mixed oxide), or byimpregnating a silica matrix with aluminum ions or alumina. Theresultant morphology is different from an alumina matrix with a full orpartial coating of silica.

The electron-withdrawing component used to treat the silica-coatedalumina solid oxide can be any component that increases the Lewis orBrønsted acidity of the solid oxide upon treatment (as compared to thesolid oxide that is not treated with at least one electron-withdrawinganion). According to one aspect of the present invention, theelectron-withdrawing component is an electron-withdrawing anion derivedfrom a salt, an acid, or other compound, such as a volatile organiccompound, that serves as a source or precursor for that anion. Examplesof suitable electron-withdrawing anions include, but are not limited to,sulfate, bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, and the like, including mixtures andcombinations thereof. In addition, other ionic or non-ionic compoundsthat serve as sources for these electron-withdrawing anions also can beemployed in the present invention. It is contemplated that theelectron-withdrawing anion can be, or can comprise, fluoride, chloride,bromide, phosphate, triflate, bisulfate, sulfate, and the like, or anycombination thereof, in some aspects of this invention. For instance,the at least one electron-withdrawing anion can comprise fluoride or,alternatively, can comprise sulfate.

According to one aspect of the present invention, an activator-supportcomprising at least one silica-coated alumina treated with at least oneelectron-withdrawing anion is contemplated. In this aspect, the at leastone silica-coated alumina has a weight ratio of alumina to silica in arange from about 1:1 to about 100:1; alternatively, from about 1.5:1 toabout 100:1; alternatively, from about 2:1 to about 20:1; oralternatively, from about 2:1 to about 12:1. Also, in this aspect, theat least one electron-withdrawing anion can comprise fluoride, chloride,bromide, phosphate, triflate, bisulfate, sulfate, or any combinationthereof; alternatively, can comprise chloride, bromide, phosphate,triflate, bisulfate, sulfate, or any combination thereof; alternatively,can comprise chloride, bromide, phosphate, sulfate, or any combinationthereof; alternatively, can comprise chloride; alternatively, cancomprise bromide; alternatively, can comprise phosphate; oralternatively, can comprise sulfate.

When the electron-withdrawing component comprises a salt of anelectron-withdrawing anion, the counterion or cation of that salt can beselected from any cation that allows the salt to revert or decomposeback to the acid during calcining. Factors that dictate the suitabilityof the particular salt to serve as a source for the electron-withdrawinganion include, but are not limited to, the solubility of the salt in thedesired solvent, the lack of adverse reactivity of the cation,ion-pairing effects between the cation and anion, hygroscopic propertiesimparted to the salt by the cation, and the like, and thermal stabilityof the anion. Examples of suitable cations in the salt of theelectron-withdrawing anion include, but are not limited to, ammonium,trialkyl ammonium, tetraalkyl ammonium, tetraalkyl phosphonium, H⁺,[H(OEt₂)₂]⁺, and the like.

Further, combinations of two or more different electron-withdrawinganions, in varying proportions, can be used to tailor the specificacidity of the activator-support to the desired level. Combinations ofelectron-withdrawing components can be contacted with the oxidematerial(s) simultaneously or individually, and in any order thataffords the desired chemically-treated solid oxide acidity. For example,one aspect of this invention is employing two or moreelectron-withdrawing anion source compounds in two or more separatecontacting steps. Hence, in aspects of this invention, anactivator-support can comprise a silica-coated alumina treated with atleast two electron-withdrawing anions. Generally, theelectron-withdrawing anions can be selected from fluoride, chloride,bromide, phosphate, triflate, bisulfate, sulfate, and the like.Accordingly, the at least two electron-withdrawing anions can comprisefluoride and phosphate, fluoride and sulfate, chloride and phosphate,chloride and sulfate, triflate and sulfate, or triflate and phosphate,in some aspects of this invention.

Thus, one example of a process by which a chemically-treatedsilica-coated alumina can be prepared is as follows: the selected solidoxide (or a combination of oxides) is contacted with a firstelectron-withdrawing anion source compound to form a first mixture; thisfirst mixture is calcined and then contacted with a secondelectron-withdrawing anion source compound to form a second mixture; thesecond mixture is then calcined to form a treated solid oxide. In such aprocess, the first and second electron-withdrawing anion sourcecompounds are either the same or different compounds, comprising thesame or different anions (e.g., fluoride and sulfate, chloride andphosphate, etc.).

According to one aspect of the present invention, an activator-supportcomprising at least one silica-coated alumina treated with at least twoelectron-withdrawing anions is contemplated. In this aspect, the atleast one silica-coated alumina has a weight ratio of alumina to silicain a range from about 1:1 to about 100:1, alternatively, from about1.5:1 to about 100:1; alternatively, from about 2:1 to about 20:1; oralternatively, from about 2:1 to about 12:1. Also, in this aspect, theat least two electron-withdrawing anions can comprise fluoride andphosphate, fluoride and sulfate, chloride and phosphate, chloride andsulfate, triflate and sulfate, or triflate and phosphate; alternatively,can comprise fluoride and phosphate; alternatively, can comprisefluoride and sulfate; alternatively, can comprise chloride andphosphate; alternatively, can comprise chloride and sulfate;alternatively, can comprise triflate and sulfate; or alternatively, cancomprise triflate and phosphate.

According to another aspect of the present invention, achemically-treated silica-coated alumina can be treated with a metalsource, including metal salts, metal ions, or other metal-containingcompounds. Non-limiting examples of the metal or metal ion can includezinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, and the like, or combinations thereof.Any method of impregnating the solid oxide with a metal can be used. Themethod by which the oxide is contacted with a metal source, typically asalt or metal-containing compound, can include, but is not limited to,gelling, co-gelling, impregnation of one compound onto another, and thelike. If desired, the metal-containing compound can be added to orimpregnated into the solid oxide in solution form, and subsequentlyconverted into the supported metal upon calcining. Accordingly, thesilica-coated alumina or chemically-treated silica-coated alumina canfurther comprise a metal or metal ion comprising zinc, titanium, nickel,vanadium, silver, copper, gallium, tin, tungsten, molybdenum, and thelike, or combinations of these metals. For example, zinc is often usedto impregnate the solid oxide because it may provide improved catalystactivity at a low cost.

The solid oxide can be treated with metal salts or metal-containingcompounds before, after, or at the same time that the solid oxide istreated with the electron-withdrawing anion. Following any contactingmethod, the contacted mixture of oxide, electron-withdrawing anion, andthe metal ion is typically calcined. Alternatively, the solid oxidematerial, the electron-withdrawing anion source, and the metal salt ormetal-containing compound are contacted and calcined simultaneously.

Various processes can be used to form chemically-treated solid oxidesuseful in the present invention. The chemically-treated solid oxide cancomprise a contact product of at least one silica-coated alumina solidoxide with one or more electron-withdrawing anion sources. It is notrequired that the silica-coated alumina solid oxide be calcined prior tocontacting the electron-withdrawing anion source. Therefore, the solidoxide can be calcined or, alternatively, the solid oxide can beuncalcined. The contact product typically is calcined either during orafter the solid oxide is contacted with the electron-withdrawing anionsource. Various processes to prepare solid oxide activator-supports thatcan be employed in this invention have been reported. For example, suchmethods are described in U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494,6,300,271, 6,316,553, 6,355,594, 6,376,415, 6,388,017, 6,391,816,6,395,666, 6,524,987, 6,548,441, 6,548,442, 6,576,583, 6,613,712,6,632,894, 6,667,274, and 6,750,302, the disclosures of which areincorporated herein by reference in their entirety.

According to one aspect of the present invention, the solid oxide ischemically-treated by contacting it with at least oneelectron-withdrawing component, typically an electron-withdrawing anionsource. Further, the solid oxide optionally is treated with a metal ion,and then calcined to form a metal-containing or metal-impregnatedchemically-treated solid oxide. According to another aspect of thepresent invention, the solid oxide and electron-withdrawing anion sourceare contacted and calcined simultaneously.

The method by which the oxide is contacted with the electron-withdrawingcomponent, typically a salt or an acid of an electron-withdrawing anion,can include, but is not limited to, gelling, co-gelling, impregnation ofone compound onto another, and the like. Thus, following any contactingmethod, the contacted mixture of the solid oxide, electron-withdrawinganion, and optional metal ion, can be, and often is, calcined.

The solid oxide activator-support (i.e., chemically-treated solidoxide), whether the inventive activator-supports of this invention oroptional, additional activator-supports (to be discussed below), thuscan be produced by a process comprising:

1) contacting at least one solid oxide with at least oneelectron-withdrawing anion source compound to form a first mixture; and

2) calcining the first mixture to form the solid oxideactivator-support.

According to another aspect of the present invention, the solid oxideactivator-support (chemically-treated solid oxide) can be produced by aprocess comprising:

1) contacting at least one solid oxide with a first electron-withdrawinganion source compound to form a first mixture;

2) calcining the first mixture to produce a calcined first mixture;

3) contacting the calcined first mixture with a secondelectron-withdrawing anion source compound to form a second mixture; and

4) calcining the second mixture to form the solid oxideactivator-support.

Generally, the at least one electron-withdrawing anion source compoundis contacted with the at least one alumina source (e.g., alumina,boehmite) after the at least one alumina source has been contacted withat least one silicon-containing compound capable of producing silicaupon calcination (e.g., silica, silicate). However, it is alsocontemplated that the electron-withdrawing anion source compound can becontacted with the at least one alumina source before—or, alternatively,at the same time as—the at least one alumina source is contacted with atleast one silicon-containing compound capable of producing silica uponcalcination.

According to yet another aspect of the present invention, thechemically-treated solid oxide is produced or formed by contacting thesolid oxide with the electron-withdrawing anion source compound, wherethe solid oxide compound is calcined before, during, or after contactingthe electron-withdrawing anion source, and where there is a substantialabsence of aluminoxanes, organoboron or organoborate compounds, andionizing ionic compounds.

Calcining of solid oxides and chemically-treated solid oxides generallyis conducted in an ambient atmosphere, typically in a dry ambientatmosphere, at a temperature from about 200° C. to about 900° C., andfor a time period of about 1 minute to about 30 hours. Calcining can beconducted at a temperature from about 300° C. to about 800° C., oralternatively, at a temperature from about 400° C. to about 700° C.Calcining can be conducted for about 30 minutes to about 50 hours, orfor about 1 hour to about 15 hours. Thus, for example, calcining can becarried out for about 1 to about 10 hours at a temperature from about350° C. to about 550° C. Any suitable ambient atmosphere can be employedduring calcining. Generally, calcining is conducted in an oxidizingatmosphere, such as air or oxygen. Alternatively, an inert atmosphere,such as nitrogen or argon, or a reducing atmosphere, such as hydrogen orcarbon monoxide, can be used.

According to one aspect of the present invention, the silica-coatedalumina solid oxide can be treated with a source of halide ion, sulfateion, or a combination of anions, optionally treated with a metal ion,and then calcined to provide the chemically-treated solid oxide in theform of a particulate solid. For example, the solid oxide material canbe treated with a source of sulfate (termed a “sulfating agent”), asource of chloride ion (termed a “chloriding agent”), a source offluoride ion (termed a “fluoriding agent”), or a combination thereof,and calcined to provide the solid oxide activator.

A chemically-treated solid oxide can comprise a fluorided silica-coatedalumina in the form of a particulate solid. The fluorided silica-coatedalumina can be formed by contacting a silica-coated alumina with afluoriding agent. The fluoride ion can be added to the oxide by forminga slurry of the oxide in a suitable solvent such as alcohol or waterincluding, but not limited to, the one to three carbon alcohols becauseof their volatility and low surface tension. Examples of suitablefluoriding agents include, but are not limited to, hydrofluoric acid(HF), ammonium fluoride (NH₄F), ammonium bifluoride (NH₄HF₂), ammoniumtetrafluoroborate (NH₄BF₄), ammonium silicofluoride (hexafluorosilicate)((NH₄)₂SiF₆), ammonium hexafluorophosphate (NH₄PF₆), hexafluorotitanicacid (H₂TiF₆), ammonium hexafluorotitanic acid ((NH₄)₂TiF₆),hexafluorozirconic acid (H₂ZrF₆), AlF₃, NH₄AlF₄, analogs thereof, andcombinations thereof. Triflic acid and ammonium triflate also can beemployed. For example, ammonium bifluoride (NH₄HF₂) can be used as thefluoriding agent, due to its ease of use and availability.

If desired, the solid oxide can be treated with a fluoriding agentduring the calcining step. Any fluoriding agent capable of thoroughlycontacting the silica-coated alumina during the calcining step can beused. For example, in addition to those fluoriding agents describedpreviously, volatile organic fluoriding agents can be used. Examples ofvolatile organic fluoriding agents useful in this aspect of theinvention include, but are not limited to, freons, perfluorohexane,perfluorobenzene, fluoromethane, trifluoroethanol, and the like, andcombinations thereof. Calcining temperatures generally must be highenough to decompose the compound and release fluoride. Gaseous hydrogenfluoride (HF) or fluorine (F₂) itself also can be used with thesilica-coated alumina if fluorided while calcining. Silicontetrafluoride (SiF₄) and compounds containing tetrafluoroborate (BF₄ ⁻)also can be employed. One convenient method of contacting silica-coatedalumina with the fluoriding agent is to vaporize a fluoriding agent intoa gas stream used to fluidize the silica-coated alumina duringcalcination.

Similarly, in another aspect of this invention, the chemically-treatedsolid oxide comprises a chlorided silica-coated alumina in the form of aparticulate solid. The chlorided solid oxide is formed by contactingsilica-coated alumina with a chloriding agent. The chloride ion can beadded to the oxide by forming a slurry of the oxide in a suitablesolvent. The silica-coated alumina can be treated with a chloridingagent during the calcining step. Any chloriding agent capable of servingas a source of chloride and thoroughly contacting the oxide during thecalcining step can be used, such as SiCl₄, SiMe₂Cl₂, TiCl₄, BCl₃, andthe like, including mixtures thereof. Volatile organic chloriding agentscan be used. Examples of suitable volatile organic chloriding agentsinclude, but are not limited to, certain freons, perchlorobenzene,chloromethane, dichloromethane, chloroform, carbon tetrachloride,trichloroethanol, and the like, or any combination thereof. Gaseoushydrogen chloride or chlorine itself also can be used with the solidoxide during calcining. One convenient method of contactingsilica-coated alumina with the chloriding agent is to vaporize achloriding agent into a gas stream used to fluidize the solid oxideduring calcination.

The amount of fluoride or chloride ion present before calcining thesilica-coated alumina solid oxide generally is from about 1 to about 50%by weight, where weight percent is based on the weight of the solidoxide before calcining. According to another aspect of this invention,the amount of fluoride or chloride ion present before calcining thesolid oxide is from about 1 to about 25% by weight, from about 2 toabout 15%, or from about 3% to about 12% by weight. According to yetanother aspect of this invention, the amount of fluoride or chloride ionpresent before calcining the solid oxide is from about 5 to about 10% byweight. Once impregnated with halide, the halided silica-coated aluminacan be dried by any suitable method including, but not limited to,suction filtration followed by evaporation, drying under vacuum, spraydrying, and the like, although it is also possible to initiate thecalcining step immediately without drying the impregnated solid oxide.

A sulfated solid oxide comprises sulfate and a solid oxide component,such as silica-coated alumina, in the form of a particulate solid.Optionally, the sulfated oxide can be treated further with a metal ionsuch that the calcined sulfated oxide comprises a metal. According toone aspect of the present invention, the sulfated solid oxide comprisessulfate and silica-coated alumina. In some instances, the sulfatedsilica-coated alumina can be formed by a process wherein thesilica-coated alumina is treated with a sulfate source, for example,sulfuric acid or a sulfate salt such as ammonium sulfate. This processis generally performed by forming a slurry of the silica-coated aluminain a suitable solvent, such as alcohol or water, in which the desiredconcentration of the sulfating agent has been added. Suitable organicsolvents include, but are not limited to, the one to three carbonalcohols because of their volatility and low surface tension.

According to one aspect of this invention, the amount of sulfate ionpresent before calcining is from about 0.5 to about 100 parts by weightsulfate ion to about 100 parts by weight solid oxide. According toanother aspect of this invention, the amount of sulfate ion presentbefore calcining is from about 1 to about 50 parts by weight sulfate ionto about 100 parts by weight solid oxide, and according to still anotheraspect of this invention, from about 5 to about 30 parts by weightsulfate ion to about 100 parts by weight solid oxide. These weightratios are based on the weight of the solid oxide before calcining. Onceimpregnated with sulfate, the sulfated silica-coated alumina can bedried by any suitable method including, but not limited to, suctionfiltration followed by evaporation, drying under vacuum, spray drying,and the like, although it is also possible to initiate the calciningstep immediately.

Generally, the silica-coated alumina activator-supports of the presentinvention are calcined. The silica-coated alumina can be calcined priorto chemical treatment, but this is not a requirement. Either during orafter chemical treatment, the silica-coated alumina activator-supportcan be calcined. Activator-supports comprising at least onesilica-coated alumina treated with at least one electron-withdrawinganion, after calcining, generally have surface areas ranging from about100 to about 1000 m²/g. In some aspects, the surface area falls within arange from about 150 to about 750 m²/g, for example, from about 200 toabout 600 m²/g. The surface area of the activator-support can range fromabout 200 to about 500 m²/g in another aspect of this invention. Forinstance, activator-supports having surface areas of about 300 m²/g,about 350 m²/g, about 400 m²/g, or about 450 m²/g, can be employed inthis invention.

After calcining, the pore volume of the activator-support is generallygreater than about 0.5 mL/g. Often, the pore volume is greater thanabout 0.75 mL/g, or greater than about 1 mL/g. In another aspect, thepore volume is greater than about 1.2 mL/g. In yet another aspect, thepore volume falls within a range from about 0.8 mL/g to about 1.8 mL/g,such as, for example, from about 1 mL/g to about 1.6 mL/g.

The calcined activator-supports disclosed herein generally have averageparticle sizes ranging from about 5 microns to about 150 microns. Insome aspects of this invention, the average particle size falls within arange from about 30 microns to about 100 microns. For example, theaverage particle size of the activator-supports can be in a range fromabout 40 to about 80 microns.

According to another aspect of the present invention, one or more oftransition metal and/or metallocene compounds can be precontacted withan olefin monomer(s) and an organoaluminum compound(s) for a firstperiod of time prior to contacting this mixture with anactivator-support (e.g., a chemically-treated silica-coated alumina).Once the precontacted mixture of the transition metal and/or metallocenecompound, olefin monomer, and organoaluminum compound is contacted withthe activator-support (one or more than one), the composition furthercomprising the activator-support is termed the “postcontacted” mixture.The postcontacted mixture can be allowed to remain in further contactfor a second period of time prior to being charged into the reactor inwhich the polymerization process will be carried out.

According to yet another aspect of the present invention, one or more oftransition metal and/or metallocene compounds can be precontacted withan olefin monomer and an activator-support (e.g., a chemically-treatedsilica-coated alumina) for a first period of time prior to contactingthis mixture with an organoaluminum compound. Once the precontactedmixture of the transition metal and/or metallocene compound, olefinmonomer, and activator-support (one or more than one) is contacted withthe organoaluminum compound, the composition further comprising theorganoaluminum is termed a “postcontacted” mixture. The postcontactedmixture can be allowed to remain in further contact for a second periodof time prior to being introduced into the polymerization reactor.

Optional Activator-Supports

The present invention encompasses various catalyst compositions whichcan include an activator-support. For example, a catalyst composition isprovided which comprises at least one metallocene or transition metalcompound and at least one activator-support. The at least oneactivator-support comprises at least one silica-coated alumina, having aweight ratio of alumina to silica ranging from about 1:1 to about 100:1,which is treated with at least one electron-withdrawing anion.

Such catalyst compositions can further comprise an additional, optionalactivator-support, such as a chemically-treated solid oxide, that isdifferent from the chemically-treated, silica-coated alumina of thepresent invention. Alternatively, the catalyst composition can furthercomprise an activator-support selected from a clay mineral, a pillaredclay, an exfoliated clay, an exfoliated clay gelled into another oxidematrix, a layered silicate mineral, a non-layered silicate mineral, alayered aluminosilicate mineral, a non-layered aluminosilicate mineral,and the like, or any combination thereof.

Generally, chemically-treated solid oxides exhibits enhanced acidity ascompared to the corresponding untreated solid oxide compound. Thechemically-treated solid oxide also functions as a catalyst activator ascompared to the corresponding untreated solid oxide. While thechemically-treated solid oxide activates the metallocene in the absenceof co-catalysts, it is not necessary to eliminate co-catalysts from thecatalyst composition. The activation function of the activator-supportis evident in the enhanced activity of catalyst composition as a whole,as compared to a catalyst composition containing the correspondinguntreated solid oxide. However, it is believed that thechemically-treated solid oxide can function as an activator, even in theabsence of organoaluminum compounds, aluminoxanes, organoboroncompounds, ionizing ionic compounds, and the like.

Chemically-treated solid oxides can comprise at least one solid oxidetreated with at least one electron-withdrawing anion. While notintending to be bound by the following statement, it is believed thattreatment of the solid oxide with an electron-withdrawing componentaugments or enhances the acidity of the oxide. Thus, either theactivator-support exhibits Lewis or Brønsted acidity that is typicallygreater than the Lewis or Brønsted acid strength of the untreated solidoxide, or the activator-support has a greater number of acid sites thanthe untreated solid oxide, or both. One method to quantify the acidityof the chemically-treated and the untreated solid oxide materials is bycomparing the polymerization activities of the treated and the untreatedoxides under acid catalyzed reactions.

Chemically-treated solid oxides of this invention are formed generallyfrom an inorganic solid oxide that exhibits Lewis acidic or Brønstedacidic behavior and has a relatively high porosity. The solid oxide ischemically-treated with an electron-withdrawing component, typically anelectron-withdrawing anion, to form an activator-support.

The pore volume and surface area of silica-coated alumina were discussedin the preceding section. Solid oxides used to prepare an additionalchemically-treated solid oxide generally have a pore volume greater thanabout 0.1 mL/g. According to another aspect of the present invention,the solid oxide has a pore volume greater than about 0.5 mL/g. Accordingto yet another aspect of the present invention, the solid oxide has apore volume greater than about 1 mL/g.

In another aspect, the solid oxide used to prepare the additionalchemically-treated solid oxide has a surface area ranging from about 100to about 1000 m²/g, for example, in a range from about 200 to about 800m²/g. In still another aspect of the present invention, the solid oxidehas a surface area in a range from about 250 to about 600 m²/g.

In still another aspect, the optional chemically-treated solid oxide cancomprise a solid inorganic oxide comprising oxygen and at least oneelement selected from Group 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,or 15 of the periodic table, or comprising oxygen and at least oneelement selected from the lanthanide or actinide elements. (See:Hawley's Condensed Chemical Dictionary, 11^(th) Ed., John Wiley & Sons;1995; Cotton, F. A., Wilkinson, G., Murillo, C. A., and Bochmann, M.,Advanced Inorganic Chemistry, 6^(th) Ed., Wiley-Interscience, 1999.) Forexample, the inorganic oxide can comprise oxygen and at least oneelement selected from Al, B, Be, Bi, Cd, Co, Cr, Cu, Fe, Ga, La, Mn, Mo,Ni, Sb, Si, Sn, Sr, Th, Ti, V, W, P, Y, Zn and Zr.

Suitable examples of solid oxide materials or compounds that can be usedto form the additional chemically-treated solid oxide include, but arenot limited to, Al₂O₃, B₂O₃, BeO, Bi₂O₃, CdO, Co₃O₄, Cr₂O₃, CuO, Fe₂O₃,Ga₂O₃, La₂O₃, Mn₂O₃, MoO₃, NiO, P₂O₅, Sb₂O₅, SiO₂, SnO₂, SrO, ThO₂,TiO₂, V₂O₅, WO₃, Y₂O₃, ZnO, ZrO₂, and the like, including mixed oxidesthereof, and combinations thereof. For example, the solid oxide that canbe used to prepare the additional chemically-treated solid oxide cancomprise silica, alumina, silica-alumina, aluminum phosphate,heteropolytungstate, titania, zirconia, magnesia, boria, zinc oxide,mixed oxides thereof, or any combination thereof. As noted above, if thesolid oxide is a silica-alumina, this material is different from thesilica-coated aluminas of the present invention, which have both highalumina content and silica coated on an alumina matrix. These knownsilica-alumina mixed oxides having an alumina to silica weight ratio ofless than 1:1 can be used to form an additional, or optional,activator-support. For example, the weight ratio of alumina to silica inthese silica-alumina mixed oxides is often in a range from about 0.05:1to about 0.25:1, as reflected in Example 1. However, thesesilica-alumina materials can optionally be used in combination with(i.e., in addition to) the high alumina content silica-coated aluminaactivator-supports of the present invention.

Solid oxides of this invention, which can be used to prepare additionalchemically-treated solid oxides, encompass oxide materials such asalumina, “mixed oxide” compounds thereof such as silica-alumina, andcombinations and mixtures thereof. Examples of mixed oxides that can beused in the additional activator-support of the present inventioninclude, but are not limited to, silica-alumina, silica-titania,silica-zirconia, zeolites, various clay minerals, alumina-titania,alumina-zirconia, zinc-aluminate, and the like.

Suitable electron-withdrawing components/anions were discussedpreviously. These can include, but are not limited to, sulfate,bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, and the like, including mixtures andcombinations thereof. Thus, for example, the optional activator-support(e.g., chemically-treated solid oxide) additionally used in the catalystcompositions of the present invention can be, or can comprise, fluoridedalumina, chlorided alumina, bromided alumina, sulfated alumina,fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, fluorided silica-zirconia,chlorided silica-zirconia, bromided silica-zirconia, sulfatedsilica-zirconia, fluorided silica-titania, and the like, or combinationsthereof.

Also, as discussed above, optional chemically-treated solid oxides canfurther comprise a metal or metal ion, such as zinc, nickel, vanadium,titanium, silver, copper, gallium, tin, tungsten, molybdenum, zirconium,and the like, or combinations thereof. Examples of additionalchemically-treated solid oxides that contain a metal or metal ion caninclude, but are not limited to, zinc-impregnated chlorided alumina,titanium-impregnated fluorided alumina, zinc-impregnated fluoridedalumina, zinc-impregnated chlorided silica-alumina, zinc-impregnatedfluorided silica-alumina, zinc-impregnated sulfated alumina, chloridedzinc aluminate, fluorided zinc aluminate, sulfated zinc aluminate, andthe like, or any combination thereof.

Methods for the preparation of, and calcination conditions for, theadditional, or optional, activator-supports can be the same as thoseprovided above in the discussion of silica-coated aluminaactivator-supports. The pore volume and surface area of silica-coatedaluminas were discussed in the preceding section, and the rangesprovided therein can be suitable for the optional, additionalactivator-supports.

According to another aspect of the present invention, the catalystcomposition can further comprise an ion-exchangeable activator-support,including but not limited to silicate and aluminosilicate compounds orminerals, either with layered or non-layered structures, andcombinations thereof. In another aspect of this invention,ion-exchangeable, layered aluminosilicates such as pillared clays areused as optional activator-supports. The ion-exchangeableactivator-support optionally can be treated with at least oneelectron-withdrawing anion such as those disclosed herein, thoughtypically the ion-exchangeable activator-support is not treated with anelectron-withdrawing anion.

According to another aspect of the present invention, the catalystcomposition further comprises clay minerals having exchangeable cationsand layers capable of expanding. Typical clay mineral activator-supportsinclude, but are not limited to, ion-exchangeable, layeredaluminosilicates such as pillared clays. Although the term “support” isused, it is not meant to be construed as an inert component of thecatalyst composition, but rather is to be considered an active part ofthe catalyst composition, because of its intimate association with thetransition metal or metallocene component.

According to another aspect of the present invention, the clay materialsof this invention encompass materials either in their natural state orthat have been treated with various ions by wetting, ion exchange, orpillaring. Typically, the clay material activator-support of thisinvention comprises clays that have been ion exchanged with largecations, including polynuclear, highly charged metal complex cations.However, the clay material activator-supports of this invention alsoencompass clays that have been ion exchanged with simple salts,including, but not limited to, salts of Al(III), Fe(II), Fe(III), andZn(II) with ligands such as halide, acetate, sulfate, nitrate, ornitrite.

According to another aspect of the present invention, the additionalactivator-support comprises a pillared clay. The term “pillared clay” isused to refer to clay materials that have been ion exchanged with large,typically polynuclear, highly charged metal complex cations. Examples ofsuch ions include, but are not limited to, Keggin ions which can havecharges such as 7+, various polyoxometallates, and other large ions.Thus, the term pillaring refers to a simple exchange reaction in whichthe exchangeable cations of a clay material are replaced with large,highly charged ions, such as Keggin ions. These polymeric cations arethen immobilized within the interlayers of the clay and when calcinedare converted to metal oxide “pillars,” effectively supporting the claylayers as column-like structures. Thus, once the clay is dried andcalcined to produce the supporting pillars between clay layers, theexpanded lattice structure is maintained and the porosity is enhanced.The resulting pores can vary in shape and size as a function of thepillaring material and the parent clay material used. Examples ofpillaring and pillared clays are found in: T. J. Pinnavaia, Science 220(4595), 365-371 (1983); J. M. Thomas, Intercalation Chemistry, (S.Whittington and A. Jacobson, eds.) Ch. 3, pp. 55-99, Academic Press,Inc., (1972); U.S. Pat. Nos. 4,452,910; 5,376,611; and 4,060,480; thedisclosures of which are incorporated herein by reference in theirentirety.

The pillaring process utilizes clay minerals having exchangeable cationsand layers capable of expanding. Any pillared clay that can enhance thepolymerization of olefins in the catalyst composition of the presentinvention can be used. Therefore, suitable clay minerals for pillaringinclude, but are not limited to, allophanes; smectites, bothdioctahedral (Al) and tri-octahedral (Mg) and derivatives thereof suchas montmorillonites (bentonites), nontronites, hectorites, or laponites;halloysites; vermiculites; micas; fluoromicas; chlorites; mixed-layerclays; the fibrous clays including but not limited to sepiolites,attapulgites, and palygorskites; a serpentine clay; illite; laponite;saponite; and any combination thereof. In one aspect, the pillared clayactivator-support comprises bentonite or montmorillonite. The principalcomponent of bentonite is montmorillonite.

The pillared clay can be pretreated if desired. For example, a pillaredbentonite is pretreated by drying at about 300° C. under an inertatmosphere, typically dry nitrogen, for about 3 hours, before beingadded to the polymerization reactor. Although an exemplary pretreatmentis described herein, it should be understood that the preheating can becarried out at many other temperatures and times, including anycombination of temperature and time steps, all of which are encompassedby this invention.

The activator-supports used to prepare the catalyst compositions of thepresent invention can be combined with other inorganic supportmaterials, including, but not limited to, zeolites, inorganic oxides,phosphated inorganic oxides, and the like. In one aspect, typicalsupport materials that are used include, but are not limited to, silica,silica-alumina, alumina, titania, zirconia, magnesia, boria, thoria,aluminophosphate, aluminum phosphate, silica-titania, coprecipitatedsilica/titania, mixtures thereof, or any combination thereof.

Transition Metal or Metallocene Compounds

The activator-supports of the present invention can be employed in acatalyst composition with one or more transition metal compounds, withone or more metallocene compounds, or combinations thereof (e.g., atleast transition metal or metallocene compound). Generally, there is nolimitation on the selection of the transition metal compound and/ormetallocene compound, or compounds, that can be used in combination withthe silica-coated alumina activator-supports disclosed herein. Forinstance, transition metal compounds disclosed in U.S. Pat. Nos.7,247,594 and 7,534,842, which are incorporated herein by reference intheir entirety, can be used with the silica-coated aluminaactivator-supports of this invention. Non-limiting examples of suchtransition metal compounds can include, but are not limited to,[bis(2,6-ditertbutylphenolato)]titanium dichloride,[tetrakis(2,6-diisopropylphenolato)]zirconium,dichloro[bis(2,6-dimethylphenolato)]zirconium bis(tetrahydrofuran),[(2,6-ditertbutyl-4-methyl)phenolato] zirconium tribenzyl,tetrakis(dimethylamido)zirconium, bis(tert-butylamido)cyclodiphosphazanezirconium dibenzyl, bis(tert-butylamido)cyclodiphosphazane zirconiumdichloride, 2,2′-methylenebis(6-tert-butyl-4-methylphenoxy)titaniumdichloride, 2,2′-thiobis(6-tert-butyl-4-methylphenoxy)titaniumdichloride, N-alkoxy-β-ketoiminate tetrahydrofuran titanium dichloride,2,2′-[1,2-ethanebis[methylamido-N]methylene]bis[4,6tert-butylphenoxy]zirconium dibenzyl,N,N′-[(amino-N)di-2,1-ethane]bis[2-N-2,4,6-trimethylphenylamido]zirconium dibenzyl, and the like, or combinations thereof.

Often, in a metallocene compound, the transition metal is Ti, Zr, Hf,Cr, La, Y, Sc, or V (or can be more than one, for example, if adinuclear metallocene compound is employed). Some examples of suitableansa-metallocene compounds include, but are not limited to:

and the like. Applicants have used the abbreviations Ph for phenyl, Mefor methyl, and t-Bu for tert-butyl.

The following representative bridged metallocene compounds also can beemployed in catalyst compositions of the present invention:

and the like.

Additional examples of bridged metallocene compounds that are suitablefor use in catalyst compositions of the present invention arecontemplated. These include, but are not limited to:

and the like.

The following non-limiting examples of two-carbon bridged metallocenecompounds also can be used in catalyst compositions of the presentinvention:

and the like. The integer n′ in these metallocene compounds generallyranges from 0 to about 10, inclusive. For example, n′ can be 1, 2, 3, 4,5, 6, 7, or 8.

Other bridged metallocene compounds can be employed in catalystcompositions of the present invention. Therefore, the scope of thepresent invention is not limited to the bridged metallocene speciesprovided above.

Likewise, unbridged metallocene compounds can be used in catalystcompositions of the present invention. Such compounds can include, butare not limited to:

and the like.

Other suitable unbridged metallocene compounds include, but are notlimited, to the following compounds:

and the like.

Additional unbridged metallocene compounds can be employed in catalystcompositions of the present invention. Therefore, the scope of thepresent invention is not limited to the unbridged metallocene speciesprovided above. Other metallocene compounds, including half-sandwich andcyclodienyl compounds, can be used in catalyst compositions of thepresent invention, and such compounds can include, but are not limitedto, the following:

and the like, wherein i-Pr is an abbreviation for isopropyl.

In accordance with one aspect of the invention, the at least onetransition metal or metallocene compound can comprise anansa-metallocene compound. In another aspect, the at least onetransition metal or metallocene compound can comprise an unbridgedmetallocene compound. In still another aspect, the at least onetransition metal or metallocene compound can comprise a dinuclearmetallocene compound. In yet another aspect of the invention, the atleast one transition metal or metallocene compound can comprise ametallocene compound (or dinuclear compound) containing an alkenylmoiety. For example, an unbridged or bridged metallocene can contain analkenyl substituent on a Cp, Ind, and/or Flu group. Alternatively, or inaddition, a bridged metallocene can contain an alkenyl substituent onthe bridging group (or the bridging atom).

Representative bridged and/or unbridged metallocene compounds which maybe employed in some aspects of this invention are disclosed in U.S. Pat.Nos. 5,498,581, 7,026,494, 7,041,617, 7,119,153, 7,148,298, 7,226,886,7,294,599, 7,312,283, 7,468,452, 7,517,939, and 7,521,572, thedisclosures of which are incorporated herein by reference in theirentirety.

In one aspect of this invention, the at least one transition metal ormetallocene compound can comprise an unbridged metallocene having thefollowing formula:(X¹)(X²)(X³)(X⁴)M¹, wherein

M¹ is Ti, Zr, or Hf;

(X¹) and (X²) independently are a substituted or unsubstituted Cp, Ind,or Flu group; and

(X³) and (X⁴) independently are a halide (e.g., fluoride, chloride,bromide, iodide), a hydride, an amido, an alkoxide, or a hydrocarbylgroup, any of which having up to 20 carbon atoms.

In another aspect of this invention, the at least one transition metalor metallocene compound can comprise a bridged metallocene having thefollowing formula:(X⁵)(X⁶)(X⁷)(X⁸)M², wherein

M² is Ti, Zr, or Hf;

(X⁵) and (X⁶) independently are a substituted Cp, Ind, or Flu group;

(X⁵) and (X⁶) are connected by a substituted or unsubstituted bridginggroup comprising a bridging chain of 2 to 5 carbon atoms, or a carbon,silicon, germanium, tin, boron, nitrogen, or phosphorus bridging atom;and

(X⁷) and (X⁸) independently are a halide, a hydride, an amido, analkoxide, or a hydrocarbyl group, any of which having up to 20 carbonatoms.

The unbridged and bridged metallocenes represented by the formulas abovecan comprise a variety of substituents. In each occurrence, anysubstituent on a substituted Cp, substituted Ind, substituted Flu, andsubstituted bridging group independently can be a hydrocarbyl group, anoxygen group, a sulfur group, a nitrogen group, a phosphorus group, anarsenic group, a carbon group, a silicon group, a germanium group, a tingroup, a lead group, a boron group, an aluminum group, an inorganicgroup, an organometallic group, or a substituted derivative thereof,having from 1 to 20 carbon atoms; a halide; or hydrogen.

A hydrocarbyl group is used herein to specify a hydrocarbon radicalgroup which includes, but is not limited to, aryl, alkyl, cycloalkyl,alkenyl, cycloalkenyl, cycloalkadienyl, alkynyl, aralkyl, aralkenyl,aralkynyl, and the like, and includes all substituted, unsubstituted,branched, linear, and/or heteroatom substituted derivatives thereof.Suitable hydrocarbyl groups can include, but are not limited to, methyl,ethyl, propyl, n-butyl, tert-butyl, sec-butyl, isobutyl, pentyl, hexyl,heptyl, octyl, nonyl, decyl, dodecyl, 2-ethylhexyl, ethenyl, propenyl,butenyl, pentenyl, hexenyl, phenyl, benzyl, tolyl, xylyl, naphthyl,cyclopentyl, cyclohexyl, and the like.

Examples of halides include fluoride, chloride, bromide, and iodide.

Oxygen groups are oxygen-containing groups, examples of which include,but are not limited to, alkoxy or aryloxy groups (—OR^(A)), —OC(O)R^(A),—OC(O)H, —OSiR^(A) ₃, —OPR^(A) ₂, —OAlR^(A) ₂, and the like, includingsubstituted derivatives thereof, wherein R^(A) in each instance isselected from alkyl, cycloalkyl, aryl, aralkyl, substituted alkyl,substituted aryl, or substituted aralkyl having from 1 to 20 carbonatoms. Examples of alkoxy or aryloxy groups (—OR^(A)) groups include,but are not limited to, methoxy, ethoxy, propoxy, butoxy, phenoxy,substituted phenoxy, and the like.

Sulfur groups are sulfur-containing groups, examples of which include,but are not limited to, —SR^(A), —OSO₂R^(A), —OSO₂OR^(A), —SCN,—SO₂R^(A), and the like, including substituted derivatives thereof,wherein R^(A) in each instance is selected from alkyl, cycloalkyl, aryl,aralkyl, substituted alkyl, substituted aryl, or substituted aralkylhaving from 1 to 20 carbon atoms.

Nitrogen groups are nitrogen-containing groups, which include, but arenot limited to, —NH₂, —NHR^(A), —NR^(A) ₂, —NO₂, —CN, and the like,including substituted derivatives thereof, wherein R^(A) in eachinstance is selected from alkyl, cycloalkyl, aryl, aralkyl, substitutedalkyl, substituted aryl, or substituted aralkyl having from 1 to 20carbon atoms.

Phosphorus groups are phosphorus-containing groups, which include, butare not limited to, —PH₂, —PHR^(A), —PR^(A) ₂, —P(O)R^(A) ₂,—P(OR^(A))₂, —P(O)(OR^(A))₂, and the like, including substitutedderivatives thereof, wherein R^(A) in each instance is selected fromalkyl, cycloalkyl, aryl, aralkyl, substituted alkyl, substituted aryl,or substituted aralkyl having from 1 to 20 carbon atoms.

Arsenic groups are arsenic-containing groups, which include, but are notlimited to, —AsHR^(A), —AsR^(A) ₂, —As(O)R^(A) ₂, —As(OR^(A))₂,—As(O)(OR^(A))₂, and the like, including substituted derivativesthereof, wherein R^(A) in each instance is selected from alkyl,cycloalkyl, aryl, aralkyl, substituted alkyl, substituted aryl, orsubstituted aralkyl having from 1 to 20 carbon atoms.

Carbon groups are carbon-containing groups, which include, but are notlimited to, alkyl halide groups that comprise halide-substituted alkylgroups with 1 to about 20 carbon atoms, aralkyl groups with 1 to about20 carbon atoms, —C(O)H, —C(O)R^(A), —C(O)OR^(A), cyano, —C(NR^(A))H,—C(NR^(A))R^(A), —C(NR^(A))OR^(A), and the like, including substitutedderivatives thereof, wherein R^(A) in each instance is selected fromalkyl, cycloalkyl, aryl, aralkyl, substituted alkyl, substituted aryl,or substituted aralkyl having from 1 to 20 carbon atoms.

Silicon groups are silicon-containing groups, which include, but are notlimited to, silyl groups such alkylsilyl groups, arylsilyl groups,arylalkylsilyl groups, siloxy groups, and the like, which in eachinstance have from 1 to 20 carbon atoms. For example, silicon groupsinclude trimethylsilyl and phenyloctylsilyl groups.

Germanium groups are germanium-containing groups, which include, but arenot limited to, germyl groups such alkylgermyl groups, arylgermylgroups, arylalkylgermyl groups, germyloxy groups, and the like, which ineach instance have from 1 to 20 carbon atoms.

Tin groups are tin-containing groups, which include, but are not limitedto, stannyl groups such alkylstannyl groups, arylstannyl groups,arylalkylstannyl groups, stannoxy (or “stannyloxy”) groups, and thelike, which in each instance have from 1 to 20 carbon atoms. Thus, tingroups include, but are not limited to, stannoxy groups.

Lead groups are lead-containing groups, which include, but are notlimited to, alkyllead groups, aryllead groups, arylalkyllead groups, andthe like, which in each instance, have from 1 to 20 carbon atoms.

Boron groups are boron-containing groups, which include, but are notlimited to, —BR^(A) ₂, —BX^(A) ₂, —BR^(A)X^(A), wherein X^(A) is amonoanionic group such as halide, hydride, alkoxide, alkyl thiolate, andthe like, and wherein R^(A) in each instance is selected from alkyl,cycloalkyl, aryl, aralkyl, substituted alkyl, substituted aryl, orsubstituted aralkyl having from 1 to 20 carbon atoms.

Aluminum groups are aluminum-containing groups, which include, but arenot limited to, —AlR^(A) ₂, —AlX^(A) ₂, —AlR^(A)X^(A), wherein X^(A) isa monoanionic group such as halide, hydride, alkoxide, alkyl thiolate,and the like, and wherein R^(A) in each instance is selected from alkyl,cycloalkyl, aryl, aralkyl, substituted alkyl, substituted aryl, orsubstituted aralkyl having from 1 to 20 carbon atoms.

Inorganic groups that may be used as substituents include, but are notlimited to, —SO₂X^(A), —OAlX^(A) ₂, —OSiX^(A) ₃, —OPX^(A) ₂, —SX^(A),—OSO₂X^(A), —AsX^(A) ₂, —As(O)X^(A) ₂, —PX^(A) ₂, and the like, whereinX^(A) is a monoanionic group such as halide, hydride, amide, alkoxide,alkyl thiolate, and the like, and wherein any alkyl, cycloalkyl, aryl,aralkyl, substituted alkyl, substituted aryl, or substituted aralkylgroup or substituent on these ligands has from 1 to 20 carbon atoms.

Organometallic groups that may be used as substituents include, but arenot limited to, organoboron groups, organoaluminum groups, organogalliumgroups, organosilicon groups, organogermanium groups, organotin groups,organolead groups, organo-transition metal groups, and the like, havingfrom 1 to 20 carbon atoms.

It is also contemplated that the at least one transition metal ormetallocene compound can comprise one or more dinuclear metallocenecompounds. Suitable dinuclear metallocenes include, but are not limitedto, those compounds disclosed in U.S. patent application Ser. No.12/489,630 and U.S. Patent Publication Nos. 2009/0170690, 2009/0170691,and 2009/0171041, the disclosures of which are incorporated herein byreference in their entirety.

Organoaluminum Compounds

In some aspects, catalyst compositions of the present invention cancomprise one or more organoaluminum compounds. Such compounds caninclude, but are not limited to, compounds having the formula:(R^(B))₃Al;where R^(B) is an aliphatic group having from 1 to 10 carbon atoms. Forexample, R^(B) can be methyl, ethyl, propyl, butyl, hexyl, or isobutyl.

Other organoaluminum compounds which can be used in catalystcompositions disclosed herein can include, but are not limited to,compounds having the formula:Al(X⁹)_(m)(X¹⁰)_(3−m),where X⁹ is a hydrocarbyl; X¹⁰ is an alkoxide or an aryloxide, a halide,or a hydride; and m is from 1 to 3, inclusive. Hydrocarbyl is usedherein to specify a hydrocarbon radical group and includes, but is notlimited to, aryl, alkyl, cycloalkyl, alkenyl, cycloalkenyl,cycloalkadienyl, alkynyl, aralkyl, aralkenyl, aralkynyl, and the like,and includes all substituted, unsubstituted, branched, linear, and/orheteroatom substituted derivatives thereof.

In one aspect, X⁹ is a hydrocarbyl having from 1 to about 20 carbonatoms. In another aspect of the present invention, X⁹ is an alkyl havingfrom 1 to 10 carbon atoms. For example, X⁹ can be methyl, ethyl, propyl,n-butyl, sec-butyl, isobutyl, or hexyl, and the like, in yet anotheraspect of the present invention.

According to one aspect of the present invention, X¹⁰ is an alkoxide oran aryloxide, any one of which has from 1 to 20 carbon atoms, a halide,or a hydride. In another aspect of the present invention, X¹⁰ isselected independently from fluorine and chlorine. Yet, in anotheraspect, X¹⁰ is chlorine.

In the formula, Al(X⁹)_(m)(X¹⁰)_(3−m), m is a number from 1 to 3,inclusive, and typically, m is 3. The value of m is not restricted to bean integer; therefore, this formula includes sesquihalide compounds orother organoaluminum cluster compounds.

Examples of organoaluminum compounds suitable for use in accordance withthe present invention include, but are not limited to, trialkylaluminumcompounds, dialkylaluminum halide compounds, dialkylaluminum alkoxidecompounds, dialkylaluminum hydride compounds, and combinations thereof.Specific non-limiting examples of suitable organoaluminum compoundsinclude trimethylaluminum (TMA), triethylaluminum (TEA),tri-n-propylaluminum (TNPA), tri-n-butylaluminum (TNBA),triisobutylaluminum (TIBA), tri-n-hexylaluminum, tri-n-octylaluminum,diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminumchloride, and the like, or combinations thereof.

The present invention contemplates a method of precontacting atransition metal and/or metallocene compound with an organoaluminumcompound and an olefin monomer to form a precontacted mixture, prior tocontacting this precontacted mixture with an activator-support to form acatalyst composition. When the catalyst composition is prepared in thismanner, typically, though not necessarily, a portion of theorganoaluminum compound is added to the precontacted mixture and anotherportion of the organoaluminum compound is added to the postcontactedmixture prepared when the precontacted mixture is contacted with thesolid oxide activator-support. However, the entire organoaluminumcompound can be used to prepare the catalyst composition in either theprecontacting or postcontacting step. Alternatively, all the catalystcomponents are contacted in a single step.

Further, more than one organoaluminum compound can be used in either theprecontacting or the postcontacting step. When an organoaluminumcompound is added in multiple steps, the amounts of organoaluminumcompound disclosed herein include the total amount of organoaluminumcompound used in both the precontacted and postcontacted mixtures, andany additional organoaluminum compound added to the polymerizationreactor. Therefore, total amounts of organoaluminum compounds aredisclosed regardless of whether a single organoaluminum compound or morethan one organoaluminum compound is used.

Aluminoxane Compounds

The present invention contemplates a catalyst composition which cancomprise an aluminoxane compound. As used herein, the term “aluminoxane”refers to aluminoxane compounds, compositions, mixtures, or discretespecies, regardless of how such aluminoxanes are prepared, formed orotherwise provided. For example, a catalyst composition comprising analuminoxane compound can be prepared in which aluminoxane is provided asthe poly(hydrocarbyl aluminum oxide), or in which aluminoxane isprovided as the combination of an aluminum alkyl compound and a sourceof active protons such as water. Aluminoxanes are also referred to aspoly(hydrocarbyl aluminum oxides) or organoaluminoxanes.

The other catalyst components typically are contacted with thealuminoxane in a saturated hydrocarbon compound solvent, though anysolvent that is substantially inert to the reactants, intermediates, andproducts of the activation step can be used. The catalyst compositionformed in this manner is collected by any suitable method, for example,by filtration. Alternatively, the catalyst composition is introducedinto the polymerization reactor without being isolated.

The aluminoxane compound of this invention can be an oligomeric aluminumcompound comprising linear structures, cyclic structures, or cagestructures, or mixtures of all three. Cyclic aluminoxane compoundshaving the formula:

wherein R is a linear or branched alkyl having from 1 to 10 carbonatoms, and p is an integer from 3 to 20, are encompassed by thisinvention. The AlRO moiety shown here also constitutes the repeatingunit in a linear aluminoxane. Thus, linear aluminoxanes having theformula:

wherein R is a linear or branched alkyl having from 1 to 10 carbonatoms, and q is an integer from 1 to 50, are also encompassed by thisinvention.

Further, aluminoxanes can have cage structures of the formula R^(t)_(5r+α)R^(b) _(r−α)Al_(4r)O_(3r), wherein R^(t) is a terminal linear orbranched alkyl group having from 1 to 10 carbon atoms; R^(b) is abridging linear or branched alkyl group having from 1 to 10 carbonatoms; r is 3 or 4; and α is equal to n_(Al(3))−n_(O(2))+n_(O(4)),wherein n_(Al(3)) is the number of three coordinate aluminum atoms,n_(O(2)) is the number of two coordinate oxygen atoms, and n_(O(4)) isthe number of 4 coordinate oxygen atoms.

Thus, aluminoxanes which can be employed in the catalyst compositions ofthe present invention are represented generally by formulas such as(R—Al—O)_(p), R(R—Al—O)_(q)AlR₂, and the like. In these formulas, the Rgroup is typically a linear or branched C₁-C₆ alkyl, such as methyl,ethyl, propyl, butyl, pentyl, or hexyl. Examples of aluminoxanecompounds that can be used in accordance with the present inventioninclude, but are not limited to, methylaluminoxane, ethylaluminoxane,n-propylaluminoxane, iso-propylaluminoxane, n-butylaluminoxane,t-butyl-aluminoxane, sec-butylaluminoxane, iso-butylaluminoxane,1-pentylaluminoxane, 2-pentylaluminoxane, 3-pentylaluminoxane,isopentylaluminoxane, neopentylaluminoxane, and the like, or anycombination thereof. Methylaluminoxane, ethylaluminoxane, andiso-butylaluminoxane are prepared from trimethylaluminum,triethylaluminum, or triisobutylaluminum, respectively, and sometimesare referred to as poly(methyl aluminum oxide), poly(ethyl aluminumoxide), and poly(isobutyl aluminum oxide), respectively. It is alsowithin the scope of the invention to use an aluminoxane in combinationwith a trialkylaluminum, such as that disclosed in U.S. Pat. No.4,794,096, incorporated herein by reference in its entirety.

The present invention contemplates many values of p and q in thealuminoxane formulas (R—Al—O)_(p) and R(R—Al—O)_(q)AlR₂, respectively.In some aspects, p and q are at least 3. However, depending upon how theorganoaluminoxane is prepared, stored, and used, the value of p and qcan vary within a single sample of aluminoxane, and such combinations oforganoaluminoxanes are contemplated herein.

In preparing a catalyst composition containing an aluminoxane, the molarratio of the total moles of aluminum in the aluminoxane (oraluminoxanes) to the total moles of transition metal and/or metallocenecompound (or compounds) in the composition is generally between about1:10 and about 100,000:1. In another aspect, the molar ratio is in arange from about 5:1 to about 15,000:1. Optionally, aluminoxane can beadded to a polymerization zone in ranges from about 0.01 mg/L to about1000 mg/L, from about 0.1 mg/L to about 100 mg/L, or from about 1 mg/Lto about 50 mg/L.

Organoaluminoxanes can be prepared by various procedures. Examples oforganoaluminoxane preparations are disclosed in U.S. Pat. Nos. 3,242,099and 4,808,561, the disclosures of which are incorporated herein byreference in their entirety. For example, water in an inert organicsolvent can be reacted with an aluminum alkyl compound, such as(R^(B))₃Al, to form the desired organoaluminoxane compound. While notintending to be bound by this statement, it is believed that thissynthetic method can afford a mixture of both linear and cyclic R—Al—Oaluminoxane species, both of which are encompassed by this invention.Alternatively, organoaluminoxanes are prepared by reacting an aluminumalkyl compound, such as (R^(B))₃Al, with a hydrated salt, such ashydrated copper sulfate, in an inert organic solvent.

Organoboron/Organoborate Compounds

According to another aspect of the present invention, a catalystcomposition further comprising organoboron or organoborate compounds isprovided. Such compounds include neutral boron compounds, borate salts,and the like, or combinations thereof. For example, fluoroorgano boroncompounds and fluoroorgano borate compounds are contemplated.

Any fluoroorgano boron or fluoroorgano borate compound can be utilizedwith the present invention. Examples of fluoroorgano borate compoundsthat can be used in the present invention include, but are not limitedto, fluorinated aryl borates such as N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, triphenylcarbeniumtetrakis(pentafluorophenyl)borate, lithiumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, triphenylcarbeniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, and the like, ormixtures thereof. Examples of fluoroorgano boron compounds that can beused as co-catalysts in the present invention include, but are notlimited to, tris(pentafluorophenyl)boron,tris[3,5-bis(trifluoromethyl)phenyl]boron, and the like, or mixturesthereof. Although not intending to be bound by the following theory,these examples of fluoroorgano borate and fluoroorgano boron compounds,and related compounds, are thought to form “weakly-coordinating” anionswhen combined with organometal or metallocene compounds, as disclosed inU.S. Pat. No. 5,919,983, the disclosure of which is incorporated hereinby reference in its entirety. Applicants also contemplate the use ofdiboron, or bis-boron, compounds or other bifunctional compoundscontaining two or more boron atoms in the chemical structure, such asdisclosed in J. Am. Chem. Soc., 2005, 127, pp. 14756-14768, the contentof which is incorporated herein by reference in its entirety.

Generally, any amount of organoboron compound can be used. According toone aspect of this invention, the molar ratio of the total moles oforganoboron or organoborate compound (or compounds) to the total molesof transition metal and/or metallocene compound (or compounds) in thecatalyst composition is in a range from about 0.1:1 to about 15:1.Typically, the amount of the fluoroorgano boron or fluoroorgano boratecompound used is from about 0.5 moles to about 10 moles of boron/boratecompound per mole of transition metal and/or metallocene compound(s).According to another aspect of this invention, the amount offluoroorgano boron or fluoroorgano borate compound is from about 0.8moles to about 5 moles of boron/borate compound per mole of transitionmetal and/or metallocene compound(s).

Ionizing Ionic Compounds

The present invention provides a catalyst composition which can furthercomprise an ionizing ionic compound. An ionizing ionic compound is anionic compound that can function as a co-catalyst to enhance theactivity of the catalyst composition. While not intending to be bound bytheory, it is believed that the ionizing ionic compound is capable ofreacting with a metallocene compound and converting the metallocene intoone or more cationic metallocene compounds, or incipient cationicmetallocene compounds. Again, while not intending to be bound by theory,it is believed that the ionizing ionic compound can function as anionizing compound by completely or partially extracting an anionicligand, possibly a non-alkadienyl ligand, from the metallocene. However,the ionizing ionic compound is an activator or co-catalyst regardless ofwhether it is ionizes the metallocene, abstracts a ligand in a fashionas to form an ion pair, weakens the metal-ligand bond in themetallocene, simply coordinates to a ligand, or activates themetallocene by some other mechanism.

Further, it is not necessary that the ionizing ionic compound activatethe transition metal and/or metallocene compound only. The activationfunction of the ionizing ionic compound can be evident in the enhancedactivity of a catalyst composition as a whole, as compared to a catalystcomposition that does not contain an ionizing ionic compound.

Examples of ionizing ionic compounds include, but are not limited to,the following compounds: tri(n-butyl)ammonium tetrakis(p-tolyl)borate,tri(n-butyl) ammonium tetrakis(m-tolyl)borate, tri(n-butyl)ammoniumtetrakis(2,4-dimethylphenyl)borate, tri(n-butyl)ammoniumtetrakis(3,5-dimethylphenyl)borate, tri(n-butyl)ammoniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, tri(n-butyl)ammoniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(p-tolyl)borate, N,N-dimethylanilinium tetrakis(m-tolyl)borate,N,N-dimethylanilinium tetrakis(2,4-dimethylphenyl)borate,N,N-dimethylanilinium tetrakis(3,5-dimethylphenyl)borate,N,N-dimethylanilinium tetrakis[3,5-bis(trifluoro-methyl)phenyl]borate,N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,triphenylcarbenium tetrakis(p-tolyl)borate, triphenylcarbeniumtetrakis(m-tolyl)borate, triphenylcarbeniumtetrakis(2,4-dimethylphenyl)borate, triphenylcarbeniumtetrakis(3,5-dimethylphenyl)borate, triphenylcarbeniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, triphenylcarbeniumtetrakis(pentafluorophenyl)borate, tropylium tetrakis(p-tolyl)borate,tropylium tetrakis(m-tolyl)borate, tropyliumtetrakis(2,4-dimethylphenyl)borate, tropyliumtetrakis(3,5-dimethylphenyl)borate, tropyliumtetrakis[3,5-bis(trifluoro-methyl)phenyl]borate, tropyliumtetrakis(pentafluorophenyl)borate, lithiumtetrakis(pentafluorophenyl)borate, lithium tetraphenylborate, lithiumtetrakis(p-tolyl)borate, lithium tetrakis(m-tolyl)borate, lithiumtetrakis(2,4-dimethylphenyl)borate, lithiumtetrakis(3,5-dimethylphenyl)borate, lithium tetrafluoroborate, sodiumtetrakis(pentafluorophenyl)borate, sodium tetraphenylborate, sodiumtetrakis(p-tolyl)borate, sodium tetrakis(m-tolyl)borate, sodiumtetrakis(2,4-dimethylphenyl)borate, sodiumtetrakis(3,5-dimethylphenyl)borate, sodium tetrafluoroborate, potassiumtetrakis-(pentafluorophenyl)borate, potassium tetraphenylborate,potassium tetrakis(p-tolyl)borate, potassium tetrakis(m-tolyl)borate,potassium tetrakis(2,4-dimethyl-phenyl)borate, potassiumtetrakis(3,5-dimethylphenyl)borate, potassium tetrafluoro-borate,lithium tetrakis(pentafluorophenyl)aluminate, lithiumtetraphenylaluminate, lithium tetrakis(p-tolyl)aluminate, lithiumtetrakis(m-tolyl)aluminate, lithiumtetrakis(2,4-dimethylphenyl)aluminate, lithiumtetrakis(3,5-dimethylphenyl)aluminate, lithium tetrafluoroaluminate,sodium tetrakis(pentafluoro-phenyl)aluminate, sodiumtetraphenylaluminate, sodium tetrakis(p-tolyl)aluminate, sodiumtetrakis(m-tolyl)aluminate, sodiumtetrakis(2,4-dimethylphenyl)aluminate, sodiumtetrakis(3,5-dimethylphenyl)aluminate, sodium tetrafluoroaluminate,potassium tetrakis(pentafluorophenyl)aluminate, potassiumtetraphenylaluminate, potassium tetrakis(p-tolyl)aluminate, potassiumtetrakis(m-tolyl)aluminate, potassiumtetrakis(2,4-dimethylphenyl)aluminate, potassium tetrakis(3,5-dimethylphenyl)aluminate, potassium tetrafluoroaluminate, and thelike, or combinations thereof. Ionizing ionic compounds useful in thisinvention are not limited to these; other examples of ionizing ioniccompounds are disclosed in U.S. Pat. Nos. 5,576,259 and 5,807,938, thedisclosures of which are incorporated herein by reference in theirentirety.

Olefin Monomers

Unsaturated reactants that can be employed with catalyst compositionsand polymerization processes of this invention typically include olefincompounds having from 2 to 30 carbon atoms per molecule and having atleast one olefinic double bond. This invention encompasseshomopolymerization processes using a single olefin such as ethylene orpropylene, as well as copolymerization, terpolymerization, etc.,reactions using an olefin monomer with at least one different olefiniccompound. For example, the resultant ethylene copolymers, terpolymers,etc., generally contain a major amount of ethylene (>50 mole percent)and a minor amount of comonomer (<50 mole percent), though this is not arequirement. Comonomers that can be copolymerized with ethylene oftenhave from 3 to 20 carbon atoms in their molecular chain.

Acyclic, cyclic, polycyclic, terminal (α), internal, linear, branched,substituted, unsubstituted, functionalized, and non-functionalizedolefins can be employed in this invention. For example, typicalunsaturated compounds that can be polymerized with the catalystcompositions of this invention include, but are not limited to,ethylene, propylene, 1-butene, 2-butene, 3-methyl-1-butene, isobutylene,1-pentene, 2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene,2-hexene, 3-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene,the four normal octenes, the four normal nonenes, the five normaldecenes, and the like, or mixtures of two or more of these compounds.Cyclic and bicyclic olefins, including but not limited to, cyclopentene,cyclohexene, norbornylene, norbornadiene, and the like, also can bepolymerized as described above. Styrene also can be employed as amonomer in the present invention. In an aspect, the olefin monomer isethylene; alternatively, the olefin monomer is propylene.

When a copolymer (or alternatively, a terpolymer) is desired, the olefinmonomer can comprise, for example, ethylene or propylene, which iscopolymerized with at least one comonomer. According to one aspect ofthis invention, the olefin monomer in the polymerization processcomprises ethylene. In this aspect, examples of suitable olefincomonomers include, but are not limited to, propylene, 1-butene,2-butene, 3-methyl-1-butene, isobutylene, 1-pentene, 2-pentene,3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 2-hexene,3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, 1-octene, 1-decene,styrene, and the like, or combinations thereof. According to one aspectof the present invention, the comonomer can comprise 1-butene,1-pentene, 1-hexene, 1-octene, 1-decene, styrene, or a combinationthereof.

Generally, the amount of comonomer introduced into a reactor zone toproduce the copolymer is from about 0.01 to about 50 weight percent ofthe comonomer based on the total weight of the monomer and comonomer.According to another aspect of the present invention, the amount ofcomonomer introduced into a reactor zone is from about 0.01 to about 40weight percent comonomer based on the total weight of the monomer andcomonomer. In still another aspect, the amount of comonomer introducedinto a reactor zone is from about 0.1 to about 35 weight percentcomonomer based on the total weight of the monomer and comonomer. Yet,in another aspect, the amount of comonomer introduced into a reactorzone is from about 0.5 to about 20 weight percent comonomer based on thetotal weight of the monomer and comonomer.

While not intending to be bound by this theory, where branched,substituted, or functionalized olefins are used as reactants, it isbelieved that a steric hindrance can impede and/or slow thepolymerization process. Thus, branched and/or cyclic portion(s) of theolefin removed somewhat from the carbon-carbon double bond would not beexpected to hinder the reaction in the way that the same olefinsubstituents situated more proximate to the carbon-carbon double bondmight. According to one aspect of the present invention, at least onemonomer/reactant is ethylene, so the polymerizations are either ahomopolymerization involving only ethylene, or copolymerizations with adifferent acyclic, cyclic, terminal, internal, linear, branched,substituted, or unsubstituted olefin. In addition, the catalystcompositions of this invention can be used in the polymerization ofdiolefin compounds including, but not limited to, 1,3-butadiene,isoprene, 1,4-pentadiene, and 1,5-hexadiene.

Polymerization Process

Catalyst compositions of the present invention can be used to polymerizeolefins to form homopolymers, copolymers, terpolymers, and the like. Onesuch olefin polymerization process comprises contacting a catalystcomposition with at least one olefin monomer and optionally at least oneolefin comonomer under polymerization conditions to produce an olefinpolymer, wherein the catalyst composition comprises at least onetransition metal or metallocene compound and at least oneactivator-support. The at least one activator-support comprises at leastone silica-coated alumina treated with at least one electron-withdrawinganion, wherein the at least one silica-coated alumina generally has aweight ratio of alumina to silica in a range from about 1:1 to about100:1. The at least one electron-withdrawing anion can comprisefluoride, chloride, bromide, phosphate, triflate, bisulfate, sulfate,and the like, or any combination thereof.

Often, a catalyst composition of the present invention, employed in anolefin polymerization process, may further comprise at least oneorganoaluminum compound. Suitable organoaluminum compounds can include,but are not limited to, trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride,diethylaluminum ethoxide, diethylaluminum chloride, and the like, orcombinations thereof.

The catalyst compositions of the present invention are intended for anyolefin polymerization method using various types of polymerizationreactors. As used herein, “polymerization reactor” includes anypolymerization reactor capable of polymerizing olefin monomers andcomonomers (one or more than one comonomer) to produce homopolymers,copolymers, terpolymers, and the like. The various types of reactorsinclude those that may be referred to as batch, slurry, gas-phase,solution, high pressure, tubular or autoclave reactors. Thepolymerization conditions for the various reactor types are well knownto those of skill in the art. Gas phase reactors may comprise fluidizedbed reactors or staged horizontal reactors. Slurry reactors may comprisevertical or horizontal loops. High pressure reactors may compriseautoclave or tubular reactors. For instance, the polymerization reactioncan be conducted in a gas phase reactor, a loop reactor, a stirred tankreactor, or a combination thereof. Reactor types can include batch orcontinuous processes. Continuous processes could use intermittent orcontinuous product discharge. Processes may also include partial or fulldirect recycle of un-reacted monomer, un-reacted comonomer, and/ordiluent.

Polymerization reactor systems of the present invention may comprise onetype of reactor in a system or multiple reactors of the same ordifferent type. Production of polymers in multiple reactors may includeseveral stages in at least two separate polymerization reactorsinterconnected by a transfer device making it possible to transfer thepolymers resulting from the first polymerization reactor into the secondreactor. The desired polymerization conditions in one of the reactorsmay be different from the operating conditions of the other reactors.Alternatively, polymerization in multiple reactors may include themanual transfer of polymer from one reactor to subsequent reactors forcontinued polymerization. Multiple reactor systems may include anycombination including, but not limited to, multiple loop reactors,multiple gas reactors, a combination of loop and gas reactors, multiplehigh pressure reactors or a combination of high pressure with loopand/or gas reactors. The multiple reactors may be operated in series orin parallel.

According to one aspect of the invention, the polymerization reactorsystem may comprise at least one loop slurry reactor comprising verticalor horizontal loops. Monomer, diluent, catalyst, and optionally anycomonomer may be continuously fed to a loop reactor where polymerizationoccurs. Generally, continuous processes may comprise the continuousintroduction of monomer/comonomer, a catalyst, and a diluent into apolymerization reactor and the continuous removal from this reactor of asuspension comprising polymer particles and the diluent. Reactoreffluent may be flashed to remove the solid polymer from the liquidsthat comprise the diluent, monomer and/or comonomer. Varioustechnologies may be used for this separation step including but notlimited to, flashing that may include any combination of heat additionand pressure reduction; separation by cyclonic action in either acyclone or hydrocyclone; or separation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess), is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, and 6,833,415,each of which is incorporated by reference in its entirety herein.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used. An example is polymerization ofpropylene monomer as disclosed in U.S. Pat. No. 5,455,314, which isincorporated by reference herein in its entirety.

According to yet another aspect of this invention, the polymerizationreactor may comprise at least one gas phase reactor. Such systems mayemploy a continuous recycle stream containing one or more monomerscontinuously cycled through a fluidized bed in the presence of thecatalyst under polymerization conditions. A recycle stream may bewithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product may be withdrawn from the reactor andnew or fresh monomer may be added to replace the polymerized monomer.Such gas phase reactors may comprise a process for multi-step gas-phasepolymerization of olefins, in which olefins are polymerized in thegaseous phase in at least two independent gas-phase polymerization zoneswhile feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. One type of gasphase reactor is disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790, and5,436,304, each of which is incorporated by reference in its entiretyherein.

According to still another aspect of the invention, a high pressurepolymerization reactor may comprise a tubular reactor or an autoclavereactor. Tubular reactors may have several zones where fresh monomer,initiators, or catalysts are added. Monomer may be entrained in an inertgaseous stream and introduced at one zone of the reactor. Initiators,catalysts, and/or catalyst components may be entrained in a gaseousstream and introduced at another zone of the reactor. The gas streamsmay be intermixed for polymerization. Heat and pressure may be employedappropriately to obtain optimal polymerization reaction conditions.

According to yet another aspect of the invention, the polymerizationreactor may comprise a solution polymerization reactor wherein themonomer/comonomer is/are contacted with the catalyst composition bysuitable stirring or other means. A carrier comprising an inert organicdiluent or excess monomer may be employed. If desired, themonomer/comonomer may be brought in the vapor phase into contact withthe catalytic reaction product, in the presence or absence of liquidmaterial. The polymerization zone is maintained at temperatures andpressures that will result in the formation of a solution of the polymerin a reaction medium. Agitation may be employed to obtain bettertemperature control and to maintain uniform polymerization mixturesthroughout the polymerization zone. Adequate means are utilized fordissipating the exothermic heat of polymerization.

Polymerization reactors suitable for the present invention may furthercomprise any combination of at least one raw material feed system, atleast one feed system for catalyst or catalyst components, and/or atleast one polymer recovery system. Suitable reactor systems for thepresent invention may further comprise systems for feedstockpurification, catalyst storage and preparation, extrusion, reactorcooling, polymer recovery, fractionation, recycle, storage, loadout,laboratory analysis, and process control.

Conditions that are controlled for polymerization efficiency and toprovide desired polymer properties include temperature, pressure, andthe concentrations of various reactants. Polymerization temperature canaffect catalyst productivity, polymer molecular weight, and molecularweight distribution. Suitable polymerization temperature may be anytemperature below the de-polymerization temperature according to theGibbs Free energy equation. Typically, this includes from about 60° C.to about 280° C., for example, or from about 60° C. to about 110° C.,depending upon the type of polymerization reactor. In some reactorsystems, the polymerization temperature can be within a range from about70° C. to about 100° C., or from about 75° C. to about 90° C.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig. Pressure for gas phasepolymerization is usually at about 200 to 500 psig. High pressurepolymerization in tubular or autoclave reactors is generally run atabout 20,000 to 75,000 psig. Polymerization reactors can also beoperated in a supercritical region occurring at generally highertemperatures and pressures. Operation above the critical point of apressure/temperature diagram (supercritical phase) may offer advantages.

According to one aspect of this invention, the ratio of hydrogen to theolefin monomer in the polymerization process can be controlled. Thisweight ratio can range from 0 ppm to about 10,000 ppm of hydrogen, basedon the weight of the olefin monomer. For instance, the reactant or feedratio of hydrogen to olefin monomer can be controlled at a weight ratiowhich falls within a range from about 10 ppm to about 7500 ppm, fromabout 10 ppm to about 5000 ppm, or from about 10 ppm to about 1000 ppm.

It is also contemplated that monomer, comonomer (or comonomers), and/orhydrogen can be periodically pulsed to the reactor, for instance, in amanner similar to that employed in U.S. Pat. No. 5,739,220 and U.S.Patent Publication No. 2004/0059070, the disclosures of which areincorporated herein by reference in their entirety.

In ethylene polymerizations, the feed ratio of hydrogen to ethylenemonomer, irrespective of comonomer(s) employed, generally is controlledat a weight ratio within a range from about 0 ppm to about 1000 ppm, butthe specific weight ratio target can depend upon the desired polymermolecular weight or melt index (MI). For ethylene polymers(homopolymers, copolymers, etc.) having a MI around 1 g/10 min, theweight ratio of hydrogen to ethylene typically can fall within a rangefrom about 5 ppm to about 300 ppm, such as, for example, from about 10ppm to about 250 ppm, or from about 10 ppm to about 200 ppm.

The concentration of the reactants entering the polymerization reactorcan be controlled to produce resins with certain physical and mechanicalproperties. The proposed end-use product that will be formed by thepolymer resin and the method of forming that product ultimately candetermine the desired polymer properties and attributes. Mechanicalproperties include tensile, flexural, impact, creep, stress relaxation,and hardness tests. Physical properties include density, molecularweight, molecular weight distribution, melting temperature, glasstransition temperature, temperature melt of crystallization, density,stereoregularity, crack growth, long chain branching, and rheologicalmeasurements.

This invention also is directed to, and encompasses, the olefin polymersproduced by any of the polymerization processes disclosed herein.Articles of manufacture can be formed from, and can comprise, the olefinpolymers produced in accordance with this invention.

Polymers and Articles

If the resultant polymer produced in accordance with the presentinvention is, for example, a polymer or copolymer of ethylene, itsproperties can be characterized by various analytical techniques knownand used in the polyolefin industry. Articles of manufacture can beformed from, and can comprise, the ethylene polymers of this invention,whose typical properties are provided below.

Polymers of ethylene (homopolymers, copolymers, terpolymers, etc.)produced in accordance with this invention generally have a melt indexfrom about 0.01 to about 100 g/10 min. Melt indices in the range fromabout 0.1 to about 50 g/10 min, or from about 0.3 to about 20 g/10 min,are contemplated in some aspects of this invention. For example, apolymer of the present invention can have a melt index in a range fromabout 0.5 to about 10, or from about 0.5 to about 6 g/10 min.

The density of ethylene-based polymers produced using one or moretransition metal and/or metallocene compounds and activator-supports ofthe present invention typically falls within the range from about 0.87to about 0.97 g/cm³. In one aspect of this invention, the density of anethylene polymer is in a range from about 0.89 to about 0.96 g/cm³. Yet,in another aspect, the density is in a range from about 0.90 to about0.95 g/cm³, such as, for example, from about 0.91 to about 0.94 g/cm³.

In one aspect, polymers of the present invention (e.g., ethylene-basedhomopolymers, copolymers, etc.) can have low levels of long chainbranching, with typically less than about 10 long chain branches (LCB)per million total carbon atoms. In some aspects, the number of longchain branches per million total carbon atoms is less than about 9;alternatively, less than about 8; alternatively, less than about 7;alternatively, less than about 6; or alternatively, less than about 5,LCB per million total carbon atoms. Furthermore, polymers of the presentinvention can have less than about 4, less than about 3, or less thanabout 2, LCB per million total carbon atoms, in other aspects of thisinvention. For example, olefin polymers of the present invention canhave about 1 LCB per million total carbon atoms, or less than about 1LCB per million total carbon atoms.

In accordance with another aspect of the present invention, a polymerproduced using a catalyst composition employing a silica-coated aluminaactivator support—for instance, fluorided silica-coated alumina—mayresult in a significant decrease in LCB content, for instance, ascompared to a polymer produced using a catalyst composition employing aconventional silica-alumina activator-support—for instance, fluoridedsilica-alumina—having an alumina to silica weight ratio of from about0.05:1 to about 0.25:1. The number of LCB's in a polymer produced usinga catalyst composition of the present invention can be less than about70% of the number of LCB's in a polymer produced using a comparablecatalyst composition containing a conventional silica-aluminaactivator-support (i.e., at the same reaction conditions, using the sameother catalyst components, same anion chemical treatment, etc.). Forinstance, the number of LCB's in a polymer produced using a catalystcomposition of the present invention can be less than about 50%, or lessthan about 35%, of the number of LCB's in a polymer produced using acomparable catalyst composition containing a conventional silica-aluminaactivator-support.

The number of LCB per million total carbon atoms can be measured from aplot of log(η₀) versus log(Mw). Linear polyethylene polymers areobserved to follow a power law relationship between their zero-shearviscosity, η₀, and their weight-average molecular weight, Mw, with apower very close to 3.4. This relationship is shown by a straight linewith a slope of 3.4 when the logarithm of η₀ is plotted versus thelogarithm of Mw. Deviations from this linear polymer line are generallyaccepted as being caused by the presence of LCB. Janzen and Colbypresented a model that predicts the expected deviation from the linearplot of log(η₀) vs. log(Mw) for given frequencies of LCB as a functionof the Mw of the polymer. See “Diagnosing long-chain branching inpolyethylenes,” J. Mol. Struct. 485-486, 569-584 (1999), which isincorporated herein by reference in its entirety. Polymers of thisinvention may deviate only slightly from the well-known 3.4 power law“Arnett line” which is used as an indication of a linear polymer (see J.Phys. Chem. 1980, 84, 649, incorporated herein by reference in itsentirety).

The CY-a parameter for olefin-based polymers disclosed herein (e.g.,ethylene-based homopolymers, copolymers, etc.) can fall within a rangefrom about 0.3 to about 0.8. In one aspect, the polymer has a CY-aparameter in a range from about 0.35 to about 0.75. In another aspect,the polymer has a CY-a parameter in a range from about 0.4 to about 0.7.In still another aspect, the polymer has a CY-a parameter in a rangefrom about 0.45 to about 0.65. In yet another aspect, the polymer has aCY-a parameter in a range from about 0.5 to about 0.6.

In accordance with another aspect of the present invention, a polymerproduced using a catalyst composition employing a silica-coated aluminaactivator support—for instance, fluorided silica-coated alumina—mayresult in a significant increase in the CY-a parameter, for instance, ascompared to a polymer produced using a catalyst composition employing aconventional silica-alumina activator-support—for instance, fluoridedsilica-alumina—having an alumina to silica weight ratio of from about0.05:1 to about 0.25:1. The CY-a parameter for a polymer produced usinga catalyst composition of the present invention can at least about 10%greater than the CY-a parameter for a polymer produced using acomparable catalyst composition containing a conventional silica-aluminaactivator-support (i.e., at the same reaction conditions, using the sameother catalyst components, same anion chemical treatment, etc.). Forinstance, the CY-a parameter for a polymer produced using a catalystcomposition of the present invention can be at least about 20%, at leastabout 30%, or at least about 50%, greater than the CY-a parameter for apolymer produced using a comparable catalyst composition containing aconventional silica-alumina activator-support.

Polymers of ethylene, whether homopolymers, copolymers, terpolymers, andso forth, can be formed into various articles of manufacture. Articleswhich can comprise polymers of this invention can include, but are notlimited to, an agricultural film, an automobile part, a bottle, a drum,a fiber or fabric, a food packaging film or container, a food servicearticle, a fuel tank, a geomembrane, a household container, a liner, amolded product, a medical device or material, a pipe, a sheet or tape, atoy, and the like. Various processes can be employed to form thesearticles. Non-limiting examples of these processes include injectionmolding, blow molding, rotational molding, film extrusion, sheetextrusion, profile extrusion, thermoforming, and the like. Additionally,additives and modifiers are often added to these polymers in order toprovide beneficial polymer processing or end-use product attributes.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Melt rheological characterizations were performed as follows.Small-strain (10%) oscillatory shear measurements were performed on aRheometrics Scientific, Inc. ARES rheometer using parallel-plategeometry. All rheological tests were performed at 190° C. The complexviscosity|η*| versus frequency (ω) data were then curve fitted using themodified three parameter Carreau-Yasuda (CY) empirical model to obtainthe zero shear viscosity—η₀, characteristic viscous relaxationtime—τ_(n), and the breadth parameter—a. The simplified Carreau-Yasuda(CY) empirical model is as follows.

${{{\eta^{*}(\omega)}} = \frac{\eta_{0}}{\lbrack {1 + ( {\tau_{\eta}\omega} )^{a}} \rbrack^{{({1 - n})}/a}}},$wherein: |η*(ω)|=magnitude of complex shear viscosity;

η₀=zero shear viscosity;

τ_(n)=viscous relaxation time;

a=“breadth” parameter;

n=fixes the final power law slope, fixed at 2/11; and

ω=angular frequency of oscillatory shearing deformation.

Details of the significance and interpretation of the CY model andderived parameters may be found in: C. A. Hieber and H. H. Chiang,Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H. Chiang, Polym. Eng.Sci., 32, 931 (1992); and R. B. Bird, R. C. Armstrong and O. Hasseger,Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2nd Edition,John Wiley & Sons (1987); each of which is incorporated herein byreference in its entirety. The CY “a” parameter (CY-a) is reported forsome of the polymer resins produced herein.

Molecular weights and molecular weight distributions were obtained usinga PL 220 SEC high temperature chromatography unit (Polymer Laboratories)with trichlorobenzene (TCB) as the solvent, with a flow rate of 1mL/minute at a temperature of 145° C. BHT(2,6-di-tert-butyl-4-methylphenol) at a concentration of 0.5 g/L wasused as a stabilizer in the TCB. An injection volume of 200 μL was usedwith a nominal polymer concentration of 1.5 mg/mL. Dissolution of thesample in stabilized TCB was carried out by heating at 150° C. for 5hours with occasional, gentle agitation. The columns used were threePLgel Mixed A LS columns (7.8×300 mm) and were calibrated with a broadlinear polyethylene standard (Phillips Marlex® BHB 5003) for which themolecular weight had been determined.

Ethylene was polymerization grade ethylene obtained from Union CarbideCorporation. This ethylene was then further purified through a column of¼-inch beads of Alcoa A201 alumina, activated at about 250° C. innitrogen. Isobutane was polymerization grade obtained from PhillipsPetroleum Company, which was further purified by distillation and thenalso passed through a column of ¼-inch beads of Alcoa A201 alumina,activated at about 250° C. in nitrogen. The 1-hexene was polymerizationgrade obtained from Chevron Chemical Company, which was further purifiedby nitrogen purging and storage over 13× molecular sieve activated atabout 250° C. Triisobutylaluminum (TIBA) was obtained from AkzoCorporation as a one molar solution in heptane.

All polymerizations were carried out in a one-gallon stirred reactor.First, the reactor was purged with nitrogen and heated to about 120° C.After cooling to below about 40° C. and purging with isobutane vapor,the metallocene compound was charged to the reactor under nitrogen. Themetallocene quantity varied based on the metallocene toactivator-support ratio, but was generally in the 0.1 to 3.5 milligramrange. Approximately 100 mg of the activator-support (A-S) were thenadded to the reactor, followed by about 0.3 mL of 1M triisobutylaluminum(TIBA) co-catalyst. The reactor was then closed and, if noted, about 48g of 1-hexene was injected into the reactor. Two liters of isobutanewere added under pressure, and the reactor was subsequently heated toabout 90° C. The reactor contents were mixed at 700 rpm. Ethylene wasthen added to the reactor and fed on demand to maintain a constant totalpressure of about 420 psig. The reactor was maintained and controlled at90° C. throughout the 60-minute run time of the polymerization. Uponcompletion, the isobutane and ethylene were vented from the reactor, thereactor was opened, and the polymer product was collected and dried.

Example 1

Synthesis of a Fluorided Silica-Alumina Activator-Support

A silica-alumina was obtained from W.R. Grace Company containing about13% alumina by weight and having a surface area of about 400 m²/g and apore volume of about 1.2 mL/g. This material was obtained as a powderhaving an average particle size of about 70 microns. Approximately 100grams of this material were impregnated with a solution containing about200 mL of water and about 10 grams of ammonium hydrogen fluoride,resulting in a damp powder having the consistency of wet sand. Thismixture was then placed in a flat pan and allowed to dry under vacuum atapproximately 110° C. for about 16 hours.

To calcine the support, about 10 grams of this powdered mixture wereplaced in a 1.75-inch quartz tube fitted with a sintered quartz disk atthe bottom. While the powder was supported on the disk, air (nitrogencan be substituted) dried by passing through a 13× molecular sievecolumn, was blown upward through the disk at the linear rate of about1.6 to 1.8 standard cubic feet per hour. An electric furnace around thequartz tube was then turned on and the temperature was raised at therate of about 400° C. per hour to the desired calcining temperature ofabout 450° C. At this temperature, the powder was allowed to fluidizefor about three hours in the dry air. Afterward, the fluoridedsilica-alumina was collected and stored under dry nitrogen, and was usedwithout exposure to the atmosphere. The fluorided silica-aluminaactivator-support of Example 1 is abbreviated A-S1. The weight ratio ofalumina to silica in A-S1 is about 0.15:1.

Example 2

Synthesis of a Sulfated Alumina Activator-Support

Boehmite was obtained from W.R. Grace Company under the designation“Alumina A” and having a surface area of about 300 m²/g and a porevolume of about 1.3 mL/g. This material was obtained as a powder havingan average particle size of about 100 microns. This material wasimpregnated to incipient wetness with an aqueous solution of ammoniumsulfate to equal about 15% sulfate. This mixture was then placed in aflat pan and allowed to dry under vacuum at approximately 110° C. forabout 16 hours.

To calcine the support, about 10 grams of this powdered mixture wereplaced in a 1.75-inch quartz tube fitted with a sintered quartz disk atthe bottom. While the powder was supported on the disk, air (nitrogencan be substituted) dried by passing through a 13× molecular sievecolumn, was blown upward through the disk at the linear rate of about1.6 to 1.8 standard cubic feet per hour. An electric furnace around thequartz tube was then turned on and the temperature was raised at therate of about 400° C. per hour to the desired calcining temperature ofabout 600° C. At this temperature, the powder was allowed to fluidizefor about three hours in the dry air. Afterward, the sulfated aluminawas collected and stored under dry nitrogen, and was used withoutexposure to the atmosphere. The sulfated alumina activator-support ofExample 2 is abbreviated A-S2.

Example 3

Synthesis of a Fluorided Silica-Coated Alumina Activator-Support

A silica-coated alumina was obtained from Sasol Company under thedesignation “Siral 28M” containing about 72% alumina by weight andhaving a surface area of about 340 m²/g and a pore volume of about 1.6mL/g. This material was obtained as a powder having an average particlesize of about 70 microns. Additional information on Siral materials canbe found in W. Daniell et al., “Enhanced surface acidity in mixedalumina-silicas: a low temperature FTIR study,” in Applied Catalysis A:General 196 (2000) 247-260, the disclosure of which is incorporatedherein by reference in its entirety. The Siral 28M was first calcined atabout 600° C. for approximately 6 hours, then impregnated to incipientwetness with a 10% ammonium bifluoride solution in methanol. Thismixture was then placed in a flat pan and allowed to dry under vacuum atapproximately 110° C. for about 16 hours.

To calcine the support, about 10 grams of this powdered mixture wereplaced in a 1.75-inch quartz tube fitted with a sintered quartz disk atthe bottom. While the powder was supported on the disk, air (nitrogencan be substituted) dried by passing through a 13× molecular sievecolumn, was blown upward through the disk at the linear rate of about1.6 to 1.8 standard cubic feet per hour. An electric furnace around thequartz tube was then turned on and the temperature was raised at therate of about 400° C. per hour to the desired calcining temperature ofabout 600° C. At this temperature, the powder was allowed to fluidizefor about three hours in the dry air. Afterward, the fluoridedsilica-coated alumina was collected and stored under dry nitrogen, andwas used without exposure to the atmosphere. The fluorided silica-coatedalumina activator-support of Example 3 is abbreviated A-S3. The weightratio of alumina to silica in A-S3 is about 2.6:1.

Example 4

Comparison of Polymerization Catalyst Activity using MET 1 and theActivator-Supports of Examples 1-3

The metallocene compound of Example 4, abbreviated “MET 1,” has thefollowing structure (Ph=Phenyl; t-Bu=tert-butyl):

The MET 1 metallocene compound can be prepared in accordance with anysuitable method. One such technique is described in U.S. PatentPublication No. 2007-0179044, the disclosure of which is incorporatedherein by reference in its entirety.

The activator-supports of Examples 1-3 were charged in separateexperiments to the reactor with various levels of MET 1, along with aconstant amount of TIBA co-catalyst. No hexene was introduced. FIG. 1illustrates the resultant polymerization catalyst activity for each ofthe three activator-supports, as a function of MET 1 toactivator-support ratio. The activity is measured in units of grams ofpolyethylene produced per gram of A-S per hour. The MET 1 concentrationvaried from about 5 to about 20 micromoles of MET 1 per gram of the A-S.FIG. 1 demonstrates that A-S3 provided better catalyst activity at lowMET 1 levels, far superior to that of A-S1 and almost twice that ofA-S2. Hence, less metallocene would be needed in a catalyst systememploying A-S3 to provide the same catalyst activity achieved with ahigher loading of metallocene with the A-S2 activator-support. Since themetallocene compound employed in a polymerization catalyst system can bean expensive component, reducing the amount of metallocene can be asignificant benefit. FIG. 1 also indicates that the activity using A-S3was comparable to that of A-S2 at the highest metallocene loading.

FIG. 2 illustrates the same polymerization catalyst activity data, butinstead, the activity is measured in units of grams of polyethyleneproduced per gram of MET 1 per hour. The catalyst activity using A-S2 isrelatively constant across the MET 1 concentration range from about 5 toabout 20 micromoles of MET 1 per gram of A-S. The higher catalystactivity of a system employing A-S3 at lower MET 1 loadings is alsoevidenced in FIG. 2.

The molecular weight and other properties of the polymer resins producedusing A-S3 are compared to those produced using A-S2, at a Met 1 loadingof 3.5 mg per 100 grams of the activator-support, in Table I below. Thepolymer produced using A-S3 had a lower molecular weight than thatproduced using A-S2.

TABLE I Property comparison of polymers produced using A-S2 and A-S3.A-S Type Mn/1000 Mw/1000 Mz/1000 PDI η₀ CY-a AS-2 87.3 212 385 2.425.86E+04 0.4615 AS-3 67.7 194 346 2.86 4.36E+04 0.4930 Notes on Table I:Mn—number-average molecular weight. Mw—weight-average molecular weight.Mz—z-average molecular weight. PDI—polydispersity index, Mw/Mn. η₀—zeroshear viscosity at 190° C. CY-a—Carreau-Yasuda breadth parameter.

Example 5

Comparison of Polymerization Catalyst Activity using MET 2 and theActivator-Supports of Examples 1-3

The metallocene compound of Example 5 was bis(n-butylcyclopentadienyl)hafnium dichloride (abbreviated “MET 2”), which can be prepared inaccordance with any suitable method for synthesizing metallocenecompounds.

The activator-supports of Examples 1-3 were charged in separateexperiments to the reactor with various levels of MET 2, along with aconstant amount of TIBA co-catalyst. For Example 5, the reactor wasmaintained and controlled at 95° C. throughout the 60-minute run time ofthe polymerization. No hexene was introduced. FIG. 3 compares theresultant polymerization catalyst activity for each of the threeactivator-supports, as a function of MET 2 to activator-support ratio.The activity is measured in units of grams of polyethylene produced pergram of A-S per hour. The MET 2 concentration varied from about 5 toabout 40 micromoles of MET 2 per gram of the A-S. FIG. 3 demonstratesthat A-S3 provided over twice the catalyst activity at all metalloceneloading levels when compared to the catalyst activity achieved usingeither A-S1 or A-S2.

FIG. 4 illustrates the same polymerization catalyst activity data, butinstead, the activity is measured in units of grams of polyethyleneproduced per gram of MET 2 per hour. Not only is the catalyst activityat all MET 2 loadings (micromoles MET 2 per gram of A-S) higher for thecatalyst system containing A-S3, but the activity at the lowestmetallocene loading is over 100,000 grams of polyethylene (per gram ofMET 2 per hour) higher than that activity of the catalyst systems usingeither A-S1 or A-S2. Thus, less metallocene can be used in a catalystsystem employing A-S3 to provide the same catalyst activity as thatachieved with much higher loadings of metallocene using either the A-S1or A-S2 activator-supports.

Example 6

Effect of Precontacting on the Polymerization Catalyst Activity of aCatalyst System Containing MET 2 and A-S3

FIG. 5 compares the grams of polyethylene produced per hour for aprecontacted catalyst system and for a catalyst system which was notprecontacted. The polymerization procedure used for the catalyst systemwhich was not precontacted was substantially the same as that employedin Example 5. In this case, however, a fixed quantity of about 0.3milligrams of MET 2 was used. For the precontacted catalyst system, theMET-2, A-S3 and TIBA were first mixed in a separate vessel for about 30minutes before being introduced into the reactor and exposed toethylene. As shown in FIG. 5, the precontacted catalyst system gave asignificant improvement in polymerization activity versus the catalystsystem which was not precontacted.

Example 7

Comparison of Polymerization Catalyst Activity using MET 3 and theActivator-Supports of Examples 2-3

The metallocene compound of Example 7, abbreviated “MET 3,” has thefollowing structure:

The MET 3 metallocene compound can be prepared in accordance with anysuitable method. One such technique is described in U.S. Pat. No.7,064,225, the disclosure of which is incorporated herein by referencein its entirety.

The activator-supports of Examples 2-3 were charged in separateexperiments to the reactor with various levels of MET 3, along with aconstant amount of TIBA co-catalyst. No hexene was introduced. FIG. 6compares the resultant polymerization catalyst activity for A-S2 andA-S3, as a function of MET 3 to activator-support ratio. The activity ismeasured in units of grams of polyethylene produced per gram of A-S perhour. The MET 3 concentration varied from about 5 to about 120micromoles of MET 3 per gram of the A-S. FIG. 6 demonstrates that A-S3provided higher catalyst activity at lower metallocene loadings on theactivator-support as compared to A-S2.

FIG. 7 illustrates the same polymerization catalyst activity data, butinstead, the activity is measured in units of grams of polyethyleneproduced per gram of MET 3 per hour. At metallocene loadings of about 60and above (micromoles MET 3 per gram of A-S), the activities of catalystsystems containing A-S2 and A-S3 appeared very similar. However, at lowmetallocene loadings, the catalyst activity was much greater for thecatalyst system employing A-S3. As mentioned above, less metallocene canbe used in a catalyst system employing A-S3 to provide the same catalystactivity as that achieved with much higher loadings of metallocene usingthe A-S2 activator-support.

Examples 8-10

Effect of Fluoride Concentration on the Activity of FluoridedSilica-Coated Alumina Activator-Supports

The silica-coated alumina support used in Examples 8-10 was the same asthe high alumina content silica-coated alumina employed in Example 3,containing about 72% alumina by weight. For Examples 8-10, thisuncalcined material was impregnated to incipient wetness with a 5%, a10%, or a 15% ammonium bifluoride solution in methanol, followed bycalcining at a temperature of about 600° C. for about three hours, inthe manner described in Example 3.

Ethylene polymerizations were conducted as described in Example 7,except that in this case, the loading of MET 3 was fixed at 3.5milligrams per 100 g of the activator-support.

Table II summarizes the catalyst activity data for Examples 8-10. Forthis set of conditions, the fluoride level at about 10 weight percentNH₄HF₂ provided the highest catalyst activity. The results in Table IIalso indicate that precalcining the silica-coated alumina support beforethe fluoride treatment also can provide an activity improvement. Forinstance, the catalyst activities in FIGS. 6-7, using a precalcinedsupport, were significantly higher than that achieved with Example 9,which did not precalcine the support prior to the fluoride treatment.

TABLE II Examples 8-10 using the MET 3 metallocene compound. FluorideActivity Activity Example Added (based on A-S) (based on MET 3) 8 5%2433 41.7 9 10% 3129 55.4 10 15% 1833 31.4 Notes on Table II: Fluorideadded is the weight percent of the NH₄HF₂ solution. Activity based onthe A-S is in units of grams of polyethylene per gram of A-S per hour.Activity based on MET 3 is in units of kilograms of polyethylene pergram of MET 3 per hour.

Examples 11-17

Effect of the Weight Ratio of Alumina to Silica on the Activity ofFluorided Silica-Coated Alumina Supports

Table III lists the silica, alumina, silica-alumina, or silica-coatedalumina supports having different ratios of alumina to silica, employedin Examples 11-17. The grade of silica-alumina used in Example 16 wasthe same as that employed in Example 1, and the grade of alumina used inExample 11 was the same as that employed in Example 2. The grade ofsilica used in Example 17 was W.R. Grace Company grade 952 silica. Thesilica-coated aluminas used in Examples 12-15 were obtained from Sasol,each made by the same technique, but with a different alumina to silicaweight ratio.

Each support was first precalcined at 600° C., then impregnated with 10%ammonium bifluoride in methanol, then calcined again at 600° C., in themanner described in Example 3. Ethylene polymerizations were conductedas described in Example 7 (e.g., 100 mg A-S, 0.3 mmol TIBA), except thatin this case, the loading of MET 3 was fixed at approximately 3.5 mg,and about 48 grams of 1-hexene were charged to the reactor.

As shown in Table III, the catalyst activities of Examples 12-15 weresuperior to the catalyst activities of Examples 11 and 16-17. Due to theexcess of MET 3 that was used, the activities based on the amount of MET3 that was employed, in units of kilograms of polyethylene per gram ofMET 3 per hour, are low.

TABLE III Examples 11-17 using the MET 3 metallocene compound. Aluminato Activity Activity Example Silica Ratio (based on A-S) (based on MET3) 11 Alumina 1688 46 12  19:1 2109 74 13   4:1 5291 192 14 2.6:1 6300200 15 1.5:1 7295 174 16 0.15:1  60 6 17 Silica 0 0 Notes on Table III:The alumina to silica ratio is the weight ratio in the silica-alumina orsilica-coated alumina support. Activity based on the A-S is in units ofgrams of polyethylene per gram of A-S per hour. Activity based on MET 3is in units of kilograms of polyethylene per gram of MET 3 per hour.

Examples 18-24

Catalyst Compositions Containing MET 3 and Silica-Coated AluminaActivator-Supports with Single and Dual Anions

The metallocene compound, MET 3, was used in Examples 18-24. Table IVlists the activator-supports employed in Examples 18-24, and therespective catalyst activity, CY-a parameter, and Tan Delta (at 0.1/sec)for each example. The sulfated alumina in Example 18 was prepared in thesame manner as in Example 2. The fluorided alumina in Example 19 wasprepared as in Example 1, except that the support was “Alumina A” fromW.R. Grace Company.

The chlorided alumina in Example 20 was prepared as follows.Approximately 10 grams of “Alumina A” from W.R. Grace Company was placedin a 2-inch quartz tube suspended on a sintered glass frit. Nitrogen waspassed up through the alumina bed at a rate of 0.1 ft/sec. An electricfurnace around the quartz tube was turned on and the temperature wasraised to about 600° C. over 1.5 hours, then about 1 mL of CCl₄ liquidwas injected and evaporated into the nitrogen stream, and contacted withthe alumina bed. The calcining step was continued for 2 hours, then thechlorided alumina was cooled and stored without exposure to theatmosphere.

The fluorided silica-alumina in Example 21 was prepared as in Example 1.The fluorided silica-coated alumina in Example 22 was prepared as inExample 3. The dual anion silica-coated aluminas in Examples 23-24 wereprepared as follows. The Siral 28M silica-coated alumina of Example 3was used for Examples 23-24, after being first calcined in air at 600°C. For the sulfated-fluorided activator-support, approximately 10 gramsof calcined silica-coated alumina was slurried in methanol containingabout 0.5 grams of ammonium bifluoride and about 0.8 grams of sulfuricacid. The methanol was then vaporized off, and the dried support wascalcined in nitrogen at 600° C. for three hours. Thephosphated-fluorided activator-support was prepared using the sameprocedure, except that 0.8 grams of phosphoric acid was used in place ofthe sulfuric acid.

Ethylene polymerizations were conducted as described in Example 7 (e.g.,100 mg A-S, 0.3 mmol TIBA), except that in this case, the loading of MET3 was fixed at approximately 3.5 mg, and about 48 grams of 1-hexene werecharged to the reactor.

As shown in Table IV, the catalyst activities of Examples 22-24 weresuperior to the catalyst activities of Examples 18-21. The CY-aparameter in Table IV can be an indicator of LCB content. Examples 22-24show significant increases in the CY-a parameter as compared to Example21.

Tan delta is the loss modulus divided by the storage modulus at a shearfrequency. The data in Table IV was taken at a low shear frequency of0.1/sec. Tan delta can be sensitive to the effects of LCB. Generally,higher tan delta means that the polymer relaxes easily, with littlestorage of the strain, and that the polymer has relatively lower LCB,assuming all other considerations are equal (e.g., molecular weight,molecular weight distribution, etc.).

TABLE IV Examples 18-24 using the MET 3 metallocene compound. ActivityExam- Alumina to based Tan ple Activator-Support Silica Ratio (on A-S)CY-a Delta 18 Sulfated Alumina Alumina 1270 0.4020 14.43 19 FluoridedAlumina Alumina 3110 0.1980 4.12 20 Chlorided Alumina Alumina 362 0.13341.53 21 Fluorided Silica- 0.15:1  1612 0.1727 7.05 Alumina 22 Fluorided2.6:1 6349 0.2204 5.44 Silica-Coated Alumina 23 Sulfated + Fluorided2.6:1 4936 0.3148 9.99 Silica-Coated Alumina 24 Phosphated + 2.6:1 51290.2940 8.79 Fluorided Silica-Coated Alumina Notes on Table IV: Thealumina to silica ratio is the weight ratio in the silica-alumina orsilica-coated alumina support. Activity based on the A-S is in units ofgrams of polyethylene per gram of A-S per hour. CY-a—Carreau-Yasudabreadth parameter.

Examples 25-32

Catalyst Compositions Containing MET 4 and Silica-Coated AluminaActivator-Supports with Single and Dual Anions

The metallocene compound of Examples 25-32 was ethylene bis-indenylzirconium dichloride (abbreviated “MET 4”), which can be prepared inaccordance with any suitable method for synthesizing metallocenecompounds.

Table V lists the activator-supports employed in Examples 25-32, and therespective catalyst activity, CY-a parameter, and Tan Delta (at 0.1/sec)for each example. The activator-supports of Examples 25-27 and 29-32were prepared as listed for the respective activator-support in Examples18-24. The phosphated-fluorided alumina of Example 28 was prepared in amanner similar to Examples 23-24, except that “Alumina A” from W.R.Grace Company was the starting material.

Ethylene polymerizations were conducted in the same manner as Examples18-24 (e.g., 100 mg A-S, 0.3 mmol TIBA), except that in this case, theloading of MET 4 was fixed at approximately 3.5 mg, and about 48 gramsof 1-hexene were charged to the reactor.

As shown in Table V, the catalyst activities of Examples 30-32 weresuperior to the catalyst activities of Examples 25-29. Examples 30-32also demonstrated significant increases in tan delta (at 0.1/sec) andthe CY-a parameter as compared to Example 29.

TABLE V Examples 25-32 using the MET 4 metallocene compound. AluminaActivity Exam- to Silica (based Tan ple Activator-Support Ratio on A-S)CY-a Delta 25 Sulfated Alumina Alumina 180 0.4734 2.89 26 FluoridedAlumina Alumina 21 0.3741 1.34 27 Chlorided Alumina Alumina 71 0.38271.88 28 Phosphated + Fluorided Alumina 455 0.5192 2.56 Alumina 29Fluorided Silica- 0.15:1  151 0.3581 1.17 Alumina 30 FluoridedSilica-Coated 2.6:1 9101 0.4759 5.78 Alumina 31 Sulfated + Fluorided2.6:1 6694 0.5588 3.69 Silica-Coated Alumina 32 Phosphated + Fluorided2.6:1 6410 0.4017 5.00 Silica-Coated Alumina Notes on Table V: Thealumina to silica ratio is the weight ratio in the silica-alumina orsilica-coated alumina support. Activity based on the A-S is in units ofgrams of polyethylene per gram of A-S per hour. CY-a—Carreau-Yasudabreadth parameter.

Examples 33-39

Synthesis of Fluorided Silica-Coated Alumina Activator-Supports havingVarying Weight Ratios of Alumina to Silica

The fluorided activator-supports of Examples 33-39 were prepared asfollows. Example 33 was prepared as in Example 26. For Examples 34-39,“Alumina A” from W.R. Grace, having a surface area of about 300 m²/g anda pore volume of 1.3 mL/g, was used as the starting material. Thealumina was first calcined at 600° C. Then, 10 gram samples of thecalcined alumina were treated with varying amounts of silicon (ortho)tetraethoxide, as follows. Each respective 10-gram alumina sample wasslurried in 50 mL of methanol, which contained a targeted amount ofSi(OEt)₄. The methanol was evaporated, and then 1 gram of ammoniumbifluoride dissolved in 30 mL of methanol was added to create a wet sandconsistency. The methanol was again evaporated and thechemically-treated solid oxide was calcined at 600° C. for 3 hours innitrogen. After cooling, the fluorided silica-coated alumina was cooled,and stored without exposure to the atmosphere.

These fluorided alumina or fluorided silica-coated aluminaactivator-supports were tested for polymerization activity with 3 mg ofMET 3 and 1 mL of 1 M TIBA in heptane (Example 35 utilized 1.8 mg of MET3). Activator-support quantities were in the 25 mg to 55 mg range.Polymerizations in 1 L of isobutane were conducted for about 30 minutesat 80° C., 450 psig reactor pressure, and a charge of 40 mL of 1-hexene.

The alumina to silica weight ratios of the fluorided activator-supportsused in Examples 33-39, and the resultant polymerization catalystactivity, are shown in Table VI. Due to the excess of MET 3 that wasused, the activities based on the amount of MET 3 that was employed, inunits of kilograms of polyethylene per gram of MET 3 per hour, arelow—compare Example 35 (1.8 mg MET 3) with Example 36 (3 mg MET 3).

TABLE VI Examples 33-39 using the MET 3 metallocene compound. Alumina toActivity Activity Example Silica Ratio (based on A-S) (based on MET 3)33 Alumina 21 0.3 34  19:1 4027 52 35 7.3:1 4042 108 36 7.3:1 6280 69 373.6:1 6277 31 38 1.8:1 5612 78 39 1.2:1 5760 120 Notes on Table VI: Thealumina to silica ratio is the weight ratio in the silica-coated aluminasupport. Activity based on the A-S is in units of grams of polyethyleneper gram of A-S per hour. Activity based on MET 3 is in units ofkilograms of polyethylene per gram of MET 3 per hour.

We claim:
 1. An activator-support comprising a silica-coated aluminatreated with an electron-withdrawing anion, wherein: the silica-coatedalumina has a weight ratio of alumina to silica in a range from about1:1 to about 2:1 and a surface area in a range from about 200 to about600 m²/g; and the electron-withdrawing anion comprises fluoride.
 2. Theactivator-support of claim 1, wherein the weight ratio of alumina tosilica is in a range from about 1.2:1 to about 1.8:1.
 3. Theactivator-support of claim 1, wherein the silica-coated alumina isfurther characterized by: a surface area in a range from about 250 toabout 500 m²/g; and a pore volume in a range from about 0.5 to about 1.8mL/g.
 4. The activator-support of claim 1, wherein the activator-supportcontains from about 2 to about 15 wt. % fluoride.
 5. Theactivator-support of claim 4, wherein the silica-coated alumina isfurther characterized by an average particle size in a range from about5 to about 150 microns.
 6. The activator-support of claim 4, wherein thesilica-coated alumina is further characterized by: a surface area in arange from about 250 to about 500 m²/g; and a pore volume in a rangefrom about 1 to about 1.6 mL/g.
 7. The activator-support of claim 6,wherein the silica-coated alumina is further characterized by an averageparticle size in a range from about 30 to about 100 microns.
 8. Theactivator-support of claim 1, wherein the activator-support is furthercharacterized by: a surface area in a range from about 200 to about 500m²/g; and a pore volume in a range from about 0.8 to about 1.8 mL/g. 9.The activator-support of claim 1, wherein: the weight ratio of aluminato silica is in a range from about 1.2:1 to about 1.8:1; and theactivator-support contains from about 3 to about 12 wt. % fluoride. 10.The activator-support of claim 9, wherein the silica-coated alumina isfurther characterized by a pore volume in a range from about 0.8 toabout 1.7 mL/g.
 11. The activator-support of claim 9, wherein theelectron-withdrawing anion further comprises sulfate or phosphate. 12.The activator-support of claim 9, wherein the activator-support isfurther characterized by: a surface area in a range from about 200 toabout 500 m²/g; and a pore volume in a range from about 1 to about 1.6mL/g.
 13. A process for preparing an activator-support, the processcomprising: contacting a silica-coated alumina with a fluoriding agentto form the activator-support; wherein the silica-coated alumina has aweight ratio of alumina to silica in a range from about 1:1 to about 2:1and a surface area in a range from about 200 to about 600 m²/g; andwherein the activator-support contains from about 2 to about 15 wt. %fluoride.
 14. The process of claim 13, further comprising a step ofdrying and/or a step of calcining after the contacting step.
 15. Theprocess of claim 13, further comprising a step of calcining thesilica-coated alumina prior to the contacting step.
 16. The process ofclaim 13, wherein a slurry of the silica-coated alumina in a solvent iscontacted with the fluoriding agent.
 17. The process of claim 13,wherein the silica-coated alumina is impregnated with a solutioncontaining the fluoriding agent and a solvent.
 18. The process of claim17, wherein the solvent comprises water or an alcohol.
 19. The processof claim 13, wherein the fluoriding agent comprises hydrofluoric acid(HF), ammonium fluoride (NH₄F), ammonium bifluoride (NH₄HF₂), ammoniumtetrafluoroborate (NH₄BF₄), ammonium hexafluorosilicate ((NH₄)₂SiF₆),ammonium hexafluorophosphate (NH₄PF₆), hexafluorotitanic acid (H₂TiF₆),ammonium hexafluorotitanic acid ((NH₄)₂TiF₆), hexafluorozirconic acid(H₂ZrF₆), AlF₃, NH₄AlF₄, triflic acid, ammonium triflate, or anycombination thereof.
 20. The process of claim 13, wherein thesilica-coated alumina is calcined while being contacted with thefluoriding agent.
 21. The process of claim 13, wherein a gas streamcontaining the fluoriding agent fluidizes the silica-coated aluminaduring calcination.
 22. The process of claim 13, wherein the fluoridingagent comprises perfluorohexane, perfluorobenzene, fluoromethane,trifluoroethanol, HF, F₂, silicon tetrafluoride (SiF₄), atetrafluoroborate (BF₄ ⁻) compound, or any combination thereof.
 23. Theprocess of claim 13, wherein: the silica-coated alumina is characterizedby a surface area in a range from about 250 to about 500 m²/g and a porevolume in a range from about 0.5 to about 1.8 mL/g; the weight ratio ofalumina to silica is in a range from about 1.2:1 to about 1.8:1; and theactivator-support contains from about 3 to about 12 wt. % fluoride.